« Oral techniques for multiplying and dividing three-digit numbers."
Goals:
1. Teach how to multiply and divide multi-digit numbers;
2. Repeat the commutative property of multiplication and the property of multiplying a sum by a number;
3. Repeat units of measurement.
4. Consolidate knowledge of the multiplication tables.
5. Build computational skills and develop logical thinking.
6. Develop cognitive activity students when studying mathematics.
Tasks: develop the ability to search for information and work with it;
develop the ability to substantiate and defend the expressed judgment;
develop motivation educational activities and interest in acquiring knowledge and ways of doing things;
cultivate interest in the subject and activity.
Org. moment
Children, today is a wonderful day. Look, I smile at you and you will smile at me. Turn to each other and smile. Well done, sit down at your desks. You can feel how warm and bright our class has become from the smiles.
Rook offers you a game called “Tangram”. Take envelopes with geometric shapes and make a silhouette drawing of a rook from them. (work in pairs).
- Look what a rook I made. Compare.
— Tell me, what figures did you use?
— How many triangles?
- What other ones? geometric figures You know?
Rook asks you to remember what you learned in previous lessons, so how will this knowledge be useful to us today?
1. Read the numbers: 540, 700, 210, 900, 650, 380,400, 820
— Indicate the number of hundreds and tens in each of them.
2. Name the number in which: 87dec., 5hundred, 64dec., 3hundred, 25dec., 49dec.,
7 hundred, 11 des.
3. Increase the numbers by 10 times: 42, 27, 91, 65, 73, 58.
2. Blitz survey
1.Volodya stayed with his grandmother for two weeks and another 4 days. How many days did Volodya stay with his grandmother? (18 days)
2. Vitya swam 26 meters. He swam 4 meters less than Seryozha. How many meters did Seryozha swim? (30 meters)
3. There are 38 old apple trees and 19 young ones in the garden. How many fewer young apple trees are there than old ones? (for 19 apple trees)
- Well done! Well done. Let `s have some rest.
3. Physical exercise
4. Introduction to the topic.
What groups can the following expressions be divided into:
15 ∙ 4 200 ∙ 4
320 ∙ 2 25 ∙ 3
Write them down in 2 columns and find the value.
— What groups did you divide these expressions into?
— Which tasks are more difficult for you to cope with? (Why do you think?)
- What was the difficulty?
(In that one column contains three-digit numbers)
- Try to install it yourself learning task for today's lesson.
(Learn to multiply and divide three-digit numbers orally)
5. Report the topic of the lesson. Setting educational objectives.
The topic of today's lesson: “Techniques mental calculations within 1000"
— What do we need to do to make it easier to solve such examples? ( Listen to the teacher’s explanation, read the information in the textbook, listen to classmates, remember the multiplication and division tables, practice solving such examples, etc.)
6. Getting to know new material.
Let's try to solve the expression: 120*4. To verbally multiply a number by a single-digit factor, perform the action, starting the multiplication not from units, as in written multiplication, otherwise: first they multiply hundreds, 100 * 4 = 400, then tens 20 * 4 = 80, after one, but we will study this later, in the end we add the resulting numbers 400 + 80 = 480
Let's try to solve the division expression: 820:2. To verbally divide a number into a single-digit factor, perform the same action as in the multiplication method. First we divide the hundreds 800:2=400, then the tens 20:2=10, then we add the results 400+10=410 Let's try to do it together:
230 * 4 = 200 * 4 + 30 * 4=920; 360: 4 =300:4(75)+60:4(15)=90
150 * 4 =100*4+50*4=600; 680: 4 =600:4(150)+80:4(20)=170
TASK. One rook, following a tractor plow, is capable of destroying 420 plant pests in a day. How many worms will a rook eat in 2 days?
— What does the problem statement say?
- What question needs to be answered?
— How many actions do you need to perform to do this?
— How can you find out how many worms a rook will eat in two days?
— Write down the solution to the problem in your notebook.
- What answer did you get?
- Who agrees with... show me.
- How did you think?
— Guys, you coped very well with the tasks that the birds offered you.
Lesson summary. Reflection.
— Guys, have we completed our tasks?
At school these actions are studied from simple to complex. Therefore, it is imperative to thoroughly understand the algorithm for performing these operations on simple examples. So that later there will be no difficulties with division decimals in a column. After all, this is the most difficult option similar tasks.
This subject requires consistent study. Gaps in knowledge are unacceptable here. Every student should learn this principle already in the first grade. Therefore, if you miss several lessons in a row, you will have to master the material on your own. Otherwise, later problems will arise not only with mathematics, but also with other subjects related to it.
Second required condition successful study mathematics - move on to examples of long division only after addition, subtraction and multiplication have been mastered.
It will be difficult for a child to divide if he has not learned the multiplication table. By the way, it is better to teach it using the Pythagorean table. There is nothing superfluous, and multiplication is easier to learn in this case.
How are natural numbers multiplied in a column?
If difficulty arises in solving examples in a column for division and multiplication, then you should begin to solve the problem with multiplication. Since division is the inverse operation of multiplication:
- Before multiplying two numbers, you need to look at them carefully. Choose the one with more digits (longer) and write it down first. Place the second one under it. Moreover, the numbers of the corresponding category must be under the same category. That is, the rightmost digit of the first number should be above the rightmost digit of the second.
- Multiply the rightmost digit of the bottom number by each digit of the top number, starting from the right. Write the answer below the line so that its last digit is under the one you multiplied by.
- Repeat the same with another digit of the lower number. But the result of multiplication must be shifted one digit to the left. In this case, its last digit will be under the one by which it was multiplied.
Continue this multiplication in a column until the numbers in the second factor run out. Now they need to be folded. This will be the answer you are looking for.
Algorithm for multiplying decimals
First, you need to imagine that the given fractions are not decimals, but natural ones. That is, remove the commas from them and then proceed as described in the previous case.
The difference begins when the answer is written down. At this moment, it is necessary to count all the numbers that appear after the decimal points in both fractions. This is exactly how many of them need to be counted from the end of the answer and put a comma there.
It is convenient to illustrate this algorithm using an example: 0.25 x 0.33:
Where to start learning division?
Before solving long division examples, you need to remember the names of the numbers that appear in the long division example. The first of them (the one that is divided) is divisible. The second (divided by) is the divisor. The answer is private.
After that, in simple everyday example Let us explain the essence of this mathematical operation. For example, if you take 10 sweets, then it’s easy to divide them equally between mom and dad. But what if you need to give them to your parents and brother?
After this, you can get acquainted with the rules of division and master them in specific examples. First simple ones, and then move on to more and more complex ones.
Algorithm for dividing numbers into a column
First, let's present the procedure for natural numbers, divisible by a single digit number. They will also be the basis for multi-digit divisors or decimal fractions. Only then should you enter minor changes, but more on that later:
- Before doing long division, you need to figure out where the dividend and divisor are.
- Write down the dividend. To the right of it is the divider.
- Draw a corner on the left and bottom near the last corner.
- Determine the incomplete dividend, that is, the number that will be minimal for division. Usually it consists of one digit, maximum of two.
- Choose the number that will be written first in the answer. It should be the number of times the divisor fits into the dividend.
- Write down the result of multiplying this number by the divisor.
- Write it under the incomplete dividend. Perform subtraction.
- Add to the remainder the first digit after the part that has already been divided.
- Choose the number for the answer again.
- Repeat multiplication and subtraction. If the remainder equal to zero and the dividend is over, then the example is done. IN otherwise repeat the steps: remove the number, pick up the number, multiply, subtract.
How to solve long division if the divisor has more than one digit?
The algorithm itself completely coincides with what was described above. The difference will be the number of digits in the incomplete dividend. Now there should be at least two of them, but if they turn out to be less than divisor, then you should work with the first three digits.
There is one more nuance in this division. The fact is that the remainder and the number added to it are sometimes not divisible by the divisor. Then you have to add another number in order. But the answer must be zero. If you are dividing three-digit numbers into a column, you may need to remove more than two digits. Then a rule is introduced: there should be one less zero in the answer than the number of digits removed.
You can consider this division using the example - 12082: 863.
- The incomplete dividend in it turns out to be the number 1208. The number 863 is placed in it only once. Therefore, the answer is supposed to be 1, and under 1208 write 863.
- After subtraction, the remainder is 345.
- You need to add the number 2 to it.
- The number 3452 contains 863 four times.
- Four must be written down as an answer. Moreover, when multiplied by 4, this is exactly the number obtained.
- The remainder after subtraction is zero. That is, the division is completed.
The answer in the example would be the number 14.
What if the dividend ends in zero?
Or a few zeros? In this case, the remainder is zero, but the dividend still contains zeros. There is no need to despair, everything is simpler than it might seem. It is enough to simply add to the answer all the zeros that remain undivided.
For example, you need to divide 400 by 5. The incomplete dividend is 40. Five fits into it 8 times. This means that the answer should be written as 8. When subtracting, there is no remainder left. That is, the division is completed, but a zero remains in the dividend. It will have to be added to the answer. Thus, dividing 400 by 5 equals 80.
What to do if you need to divide a decimal fraction?
Again, this number looks like a natural number, if not for the comma separating the whole part from the fractional part. This suggests that the division of decimal fractions into a column is similar to that described above.
The only difference will be the semicolon. It is supposed to be put in the answer as soon as the first digit from the fractional part is removed. Another way to say this is this: if you have finished dividing the whole part, put a comma and continue the solution further.
When solving examples of long division with decimal fractions, you need to remember that any number of zeros can be added to the part after the decimal point. Sometimes this is necessary in order to complete the numbers.
Dividing two decimals
It may seem complicated. But only at the beginning. After all, how to divide a column of fractions by a natural number is already clear. This means that we need to reduce this example to an already familiar form.
It's easy to do. You need to multiply both fractions by 10, 100, 1,000 or 10,000, and maybe by a million if the problem requires it. The multiplier is supposed to be chosen based on how many zeros are in the decimal part of the divisor. That is, the result will be that you will have to divide the fraction by a natural number.
Moreover, this will be in worst case. After all, it may happen that the dividend from this operation becomes an integer. Then the solution to the example with division into a column of fractions will be reduced to the very simple option: operations with natural numbers.
As an example: divide 28.4 by 3.2:
- They must first be multiplied by 10, since the second number has only one digit after the decimal point. Multiplying will give 284 and 32.
- They are supposed to be separated. Moreover, the whole number is 284 by 32.
- The first number chosen for the answer is 8. Multiplying it gives 256. The remainder is 28.
- The division of the whole part has ended, and a comma is required in the answer.
- Remove to remainder 0.
- Take 8 again.
- Remainder: 24. Add another 0 to it.
- Now you need to take 7.
- The result of multiplication is 224, the remainder is 16.
- Take down another 0. Take 5 each and you get exactly 160. The remainder is 0.
The division is complete. The result of example 28.4:3.2 is 8.875.
What if the divisor is 10, 100, 0.1, or 0.01?
Just like with multiplication, long division is not needed here. It is enough to simply move the comma in the desired direction for a certain number of digits. Moreover, using this principle, you can solve examples with both integers and decimal fractions.
So, if you need to divide by 10, 100 or 1,000, then the decimal point is moved to the left by the same number of digits as there are zeros in the divisor. That is, when a number is divisible by 100, the decimal point must move to the left by two digits. If the dividend is a natural number, then it is assumed that the comma is at the end.
This action gives the same result as if the number were to be multiplied by 0.1, 0.01 or 0.001. In these examples, the comma is also moved to the left by the number of digits, equal to length fractional part.
When dividing by 0.1 (etc.) or multiplying by 10 (etc.), the decimal point should move to the right by one digit (or two, three, depending on the number of zeros or the length of the fractional part).
It is worth noting that the number of digits given in the dividend may not be sufficient. Then the missing zeros can be added to the left (in the whole part) or to the right (after the decimal point).
Division of periodic fractions
In this case, it will not be possible to obtain an accurate answer when dividing into a column. How to solve an example if you encounter a fraction with a period? Here we need to move on to ordinary fractions. And then divide them according to the previously learned rules.
For example, you need to divide 0.(3) by 0.6. The first fraction is periodic. It converts to the fraction 3/9, which when reduced gives 1/3. The second fraction is the final decimal. It’s even easier to write it down as usual: 6/10, which is equal to 3/5. The rule for dividing ordinary fractions prescribes replacing division with multiplication and divisor - reciprocal number. That is, the example comes down to multiplying 1/3 by 5/3. The answer will be 5/9.
If the example contains different fractions...
Then several solutions are possible. Firstly, common fraction You can try to convert it to decimal. Then divide two decimals using the above algorithm.
Secondly, every final decimal fraction can be written as a common fraction. But this is not always convenient. Most often, such fractions turn out to be huge. And the answers are cumbersome. Therefore, the first approach is considered more preferable.
Division is one of the four basic mathematical operations (addition, subtraction, multiplication). Division, like other operations, is important not only in mathematics, but also in Everyday life. For example, you as a whole class (25 people) donate money and buy a gift for the teacher, but you don’t spend it all, there will be change left over. So you will need to divide the change among everyone. The division operation comes into play to help you solve this problem.
Division is an interesting operation, as we will see in this article!
Dividing numbers
So, a little theory, and then practice! What is division? Division is breaking something into equal parts. That is, it could be a bag of sweets that needs to be divided into equal parts. For example, there are 9 candies in a bag, and the person who wants to receive them is three. Then you need to divide these 9 candies among three people.
It is written like this: 9:3, the answer will be the number 3. That is, dividing the number 9 by the number 3 shows the number of numbers three contained in the number 9. Reverse action, the test will be multiplication. 3*3=9. Right? Absolutely.
So let's look at example 12:6. First, let's name each component of the example. 12 – dividend, that is. a number that can be divided into parts. 6 is a divisor, this is the number of parts into which the dividend is divided. And the result will be a number called “quotient”.
Let's divide 12 by 6, the answer will be the number 2. You can check the solution by multiplying: 2*6=12. It turns out that the number 6 is contained 2 times in the number 12.
Division with remainder
What is division with a remainder? This is the same division, only the result is not an even number, as shown above.
For example, let's divide 17 by 5. Since the largest number divisible by 5 to 17 is 15, then the answer will be 3 and the remainder is 2, and is written like this: 17:5 = 3(2).
For example, 22:7. In the same way, we determine the maximum number divisible by 7 to 22. This number is 21. The answer then will be: 3 and the remainder 1. And it is written: 22:7 = 3 (1).
Division by 3 and 9
A special case of division would be division by the number 3 and the number 9. If you want to find out whether a number is divisible by 3 or 9 without a remainder, then you will need:
Find the sum of the digits of the dividend.
Divide by 3 or 9 (depending on what you need).
If the answer is obtained without a remainder, then the number will be divided without a remainder.
For example, the number 18. The sum of the digits is 1+8 = 9. The sum of the digits is divisible by both 3 and 9. The number 18:9=2, 18:3=6. Divided without remainder.
For example, the number 63. The sum of the digits is 6+3 = 9. Divisible by both 9 and 3. 63:9 = 7, and 63:3 = 21. Such operations are carried out with any number to find out whether it is divisible with the remainder by 3 or 9, or not.
Multiplication and division
Multiplication and division are opposite operations. Multiplication can be used as a test for division, and division can be used as a test for multiplication. You can learn more about multiplication and master the operation in our article about multiplication. Which describes multiplication in detail and how to do it correctly. There you will also find the multiplication table and examples for training.
Here is an example of checking division and multiplication. Let's say the example is 6*4. Answer: 24. Then let's check the answer by division: 24:4=6, 24:6=4. It was decided correctly. In this case, the check is performed by dividing the answer by one of the factors.
Or an example is given for the division 56:8. Answer: 7. Then the test will be 8*7=56. Right? Yes. IN in this case verification is done by multiplying the answer by the divisor.
Division 3 class
In third grade they are just starting to go through division. Therefore, third graders solve the simplest problems:
Problem 1. A factory worker was given the task of putting 56 cakes into 8 packages. How many cakes should be put in each package to make the same amount in each?
Problem 2. On New Year's Eve at school, children in a class of 15 students were given 75 candies. How many candies should each child receive?
Problem 3. Roma, Sasha and Misha picked 27 apples from the apple tree. How many apples will each person get if they need to be divided equally?
Problem 4. Four friends bought 58 cookies. But then they realized that they could not divide them equally. How many additional cookies do the kids need to buy so that each gets 15?
Division 4th grade
The division in the fourth grade is more serious than in the third. All calculations are carried out using the column division method, and the numbers involved in the division are not small. What is long division? You can find the answer below:
Column division
What is long division? This is a method that allows you to find the answer to division. large numbers. If prime numbers like 16 and 4, can be divided, and the answer is clear - 4. That 512:8 in the mind is not easy for a child. And tell us about the solution technique similar examples- our task.
Let's look at an example, 512:8.
1 step. Let's write the dividend and divisor as follows:
The quotient will ultimately be written under the divisor, and the calculations under the dividend.
Step 2. We start dividing from left to right. First we take the number 5: 
Step 3. The number 5 is less than the number 8, which means it will not be possible to divide. Therefore, we take another digit of the dividend:
Now 51 is greater than 8. This is an incomplete quotient.
Step 4. We put a dot under the divisor.
Step 5. After 51 there is another number 2, which means there will be one more number in the answer, that is. quotient is a two-digit number. Let's put the second point:
Step 6. We begin the division operation. Largest number, divisible by 8 without a remainder to 51 – 48. Dividing 48 by 8, we get 6. Write the number 6 instead of the first dot under the divisor:
Step 7. Then write the number exactly below the number 51 and put a “-” sign:
Step 8. Then we subtract 48 from 51 and get the answer 3.
* 9 step*. We take down the number 2 and write it next to the number 3:
Step 10 We divide the resulting number 32 by 8 and get the second digit of the answer – 4.
So the answer is 64, without remainder. If we divided the number 513, then the remainder would be one.
Division of three digits
Dividing three-digit numbers is done using the long division method, which was explained in the example above. An example of just a three-digit number.
Division of fractions
Dividing fractions is not as difficult as it seems at first glance. For example, (2/3):(1/4). The method of this division is quite simple. 2/3 is the dividend, 1/4 is the divisor. You can replace the division sign (:) with multiplication ( ), but to do this you need to swap the numerator and denominator of the divisor. That is, we get: (2/3)(4/1), (2/3)*4, this is equal to 8/3 or 2 integers and 2/3. Let's give another example, with an illustration for better understanding. Consider the fractions (4/7):(2/5):
As in the previous example, we reverse the 2/5 divisor and get 5/2, replacing division with multiplication. We then get (4/7)*(5/2). We make a reduction and answer: 10/7, then take out the whole part: 1 whole and 3/7.
Dividing numbers into classes
Let's imagine the number 148951784296, and divide it into three digits: 148,951,784,296. So, from right to left: 296 is the class of units, 784 is the class of thousands, 951 is the class of millions, 148 is the class of billions. In turn, in each class 3 digits have their own digit. From right to left: the first digit is units, the second digit is tens, the third is hundreds. For example, the class of units is 296, 6 is ones, 9 is tens, 2 is hundreds.
Division of natural numbers
Division of natural numbers is the simplest division described in this article. It can be either with or without a remainder. The divisor and dividend can be any non-fractional, integer numbers. 
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Division presentation
Presentation is another way to visualize the topic of division. Below we will find a link to an excellent presentation that does a good job of explaining how to divide, what division is, what dividend, divisor and quotient are. Don’t waste your time, but consolidate your knowledge!
Examples for division
Easy level
Average level
Difficult level
Games for developing mental arithmetic
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Summary of a mathematics lesson in 3rd grade. Program "School 2100".
Technology "Problematic dialogue"
Topic: Multiplication and division of round three-digit numbers (carryover lesson existing knowledge to a new numerical concentration).
Goal: to discover a method of oral techniques for multiplying and dividing round three-digit numbers, similar to the same techniques for multiplying and dividing double digit numbers.
Tasks:
repeat oral techniques for multiplying and dividing two-digit numbers;
create an algorithm for oral techniques for multiplying and dividing round three-digit numbers, similar to the same techniques for multiplying and dividing two-digit numbers;
solve text problems of the studied type at the new numerical concentration;
During the classes:
Org moment.
Before lesson start,
I want to wish you:
Be attentive in your studies
And learn with passion.
A situation of success. Updating knowledge.
Mathematical dictation.
Where does a math lesson usually start?
Why do we write mathematical dictations?
Let's practice some calculations.
Find a number that is 3 times greater than 20.
Find a number that is 6 times less than 78.
Find the product of 23 and 4.
Find the quotient of 90 and 5.
Examination.
Write down all three-digit numbers that can be made from the numbers 2,6,0.
Tell me how many tens there are in these numbers. How many hundreds are there in these numbers?
Examination. Self-assessment of work by students.
Gap situation. Introduction to the topic of the lesson.
Here's ours next task. What do you think is the purpose of the task?
There are 2 columns of examples on the board. The first option solves the examplesIcolumn, second option - examplesIIcolumn. (Examples are solved for a while).
16*6 840:4
84:7 130*5
13*5 360:6
72:4 840:7
84:4 160*6
36:6 720:4
Let's check.
Which option completed the task better, faster?
Why? How are the example columns different? (INIcolumn examples on multiplication and division of two-digit numbers by single-digit numbers).
Are we good at this?
How are the examples different?IIcolumn? (More difficult. Here are examples of multiplying and dividing three-digit numbers by single-digit numbers).
We can do this, do we know? What can't we do? (We don’t know how to multiply and divide three-digit numbers).
How are all three-digit numbers in column 2 similar? (they end with 0, round)
Setting the lesson goal.
What is the purpose of our lesson today? (Learn to multiply and divide round three-digit numbers by single-digit numbers). What is the topic of the lesson?
Physical education minute.
Discovery of new knowledge. (Group work)
I think that you can handle this task yourself. Today I will give you different examples. Try to discover for yourself how to multiply and divide three-digit numbers by one-digit numbers.
Children work in a group.
Examples: 1st row – 840:40 2nd row – 130*5 3rd row – 400*2
Selecting the required method of action.
The groups put their decisions on the board. Solutions are compared. More than one is selected rational way solutions.
Question for row 3:
Is it possible to divide 400 by 2 using the same method?
Formulation of the rule.
How can you multiply or divide round three-digit numbers by single-digit numbers? (Three-digit numbers can be expressed in tens and hundreds and perform multiplication and division as two-digit numbers; turn into easier examples within 100 by expressing three-digit numbers in tens and hundreds)
Compare your conclusions with the conclusions given in the textbook on p. 74.
Does our conclusion match the conclusions given in the textbook?
Guys, have we achieved the goal of the lesson?
DID YOU UNDERSTAND A NEW TOPIC? (Self-assessment of understanding of the topic - in the margins of the notebook, the guys draw a self-assessment (self-assessment technique - emoticon)
Application of new knowledge.
Explanation of the solution to examples No. 4 on p. 74 of the textbook.
Solving problems No. 2,3 on p. 74 of the textbook.
Consolidation of what has been learned.
Solving problems No. 6 on p. 75 of the textbook. (Solution at the new numerical concentration word problems studied species).
Lesson summary:
Summary:
What was the topic of the lesson? What was our goal? What is the method for multiplying and dividing round three-digit numbers? (Convert them to tens and hundreds and perform multiplication and division as with two-digit numbers).
2) Reflection:
What did you like most about the lesson? What was difficult? Do you understand the topic of the lesson? Evaluate your work in class.
3) Homework: No. 5,7 on p. 29 of the textbook.
Mathematics lesson on the topic "Multiplying and dividing three-digit numbers by a single-digit number without going through the place value."
Target: consolidate the knowledge, skills and abilities of multiplying and dividing a three-digit number by a single-digit number without going through a digit; develop skills to apply in practice theoretical knowledge, problem solving skills; develop verbal-logical thinking through staging problematic issues, attentiveness, intelligence, independence; bring up moral qualities by organizing mutual assistance, discussing the qualities needed in the lesson. positive lesson motivation.
Equipment: computer, overhead projector, presentation, cards.
DURING THE CLASSES
Breathing exercise “New lesson”.
On entertaining lesson
A loud bell started.
Are you ready to count?
Divide and multiply quickly.
- What qualities and learning skills will we need in the classroom? Select.
(slide No. 2)
Quick wit
Savvy
Laziness
Attention
Noise
Perseverance
- Do we take them with us to class?
II. Checking homework
Attention! Attention!
We start the lesson by checking homework.
Homework: No. 745, p. 160.
(slide No. 3)
"Find the extra number"
321, 222, 243, 212, 444, 221, 214, 211, 311, 142, 123
(slide 2)
- Who agrees with the number?
Children raise their hands.
Create an example whose answer can be 444.
What else was assigned at home?
2. Mathematical dictation.
Product of numbers 8 and 9;
quotient of 36 and 4;
increase 8 by 6 times;
reduce 27 by 3 times;
How many times is 15 greater than 3?
1 factor is 9, the second is the same, what is the product equal to;
dividend 42, quotient 7, what is the divisor;
What number cannot be divided by?
Now check yourself!(Slide No. 4)
b) On next questions you answer either “yes” or “no”
All three-digit numbers are odd;
All three-digit numbers are greater than 9;
If a number is multiplied by 1, it becomes 1;
If a number is divided by itself, the result is 0;
All even numbers divisible by 2
Some three-digit numbers are less than 9;
You cannot divide by 0;
When you multiply a number by 1, you get the same number;
Test yourself!(Slide No. 4)
III. Verbal counting
(slide 5)
1. One T-shirt in the store costs 80 rubles. How much money do you need to pay to buy T-shirts for all the boys in our class?(80 rub. x 8 = 640 rub.)
2. We bought skirts for the girls in our class. We paid 250 rubles for the entire purchase. How much does one skirt cost?(250r.:1=250r.)
3. The school purchased 200 packs of laundry soap. Each pack costs 5 rubles. Count total amount purchase price.(5 rubles x 200 = 1000 rubles)
- What did we repeat when solving this problem?(We repeated the multiplication and division tables.)
IV. State the topic and purpose of the lesson.
V. Fixing the material.
a) Solving the problem using short notation
(slide No. 6)
- Think and compose a problem, starting with the words:
In a week our school spends...
- What is this task about?(This problem is about vegetables: potatoes and carrots.)
- What is known in the problem?(It is known that potatoes488 kg consumed.)
- What is said about carrots?(Carrots are consumed 4 times less than potatoes.)
- How do we find out how many carrots have been used?(Division action 488: 4 = 122 kg)
- Is it possible to answer the problem question now?(Let's add potatoes and carrots together and answer the question in the problem.)
Solving the problem on the board and in notebooks with comments
Physical exercise.
a) Game “Sharing - not sharing”
(Slide No. 7)
- I name a couple of numbers. Your task: if the numbers are divided among themselves, then you quietly get up; If they don’t share, then clap your hands.
248: 2 = ;
367: 3 = ;
848: 4 = ;
481: 2 = ;
936: 3 = ;
695: 3 = .
b) Exercise for the eyes. (Slide No. 8,9)
Watch carefully the movement of the multi-colored circles!
VI. Consolidation
a) Write down only the answers. (Slide No. 10)
Check (Slide No. 11).
b) Working with the textbook.
Page 160 No. 741 - at the blackboard.
Analysis and analysis of the problem.
c) Independent work
223
450
101
777
684
969
Peer review.
VII. Homework. (slide No. 12)
- At home you should solve No. 747p. 160.
(Analysis of d/z).
VII. Lesson summary. Grading.
Reflection (Today in class I….).