Adding and subtracting two-digit and single-digit numbers

LESSON TOPIC: « Subtraction single digit numbers out of 10"
GOALS:
PERSONAL UNIVERSAL LEARNING ACTIONS
Master the roles of the student; create interest in learning.
REGULATORY UNIVERSAL TRAINING ACTIONS.

Learn to plan your actions in accordance with the task, develop the ability to evaluate the correctness of your actions.

Organize your workplace under the guidance of a teacher.

COGNITIVE UNIVERSAL LEARNING ACTIONS.

To develop the ability to work with a textbook as a source of information, in the context of solving educational problems, and to answer simple questions from the teacher.

Consider a method for subtracting single-digit numbers from 10.

Continue developing the skills of subtraction and addition within 20 based on knowledge of the composition of the number and using the “Addition Table”.

Improve the ability to establish connections between actions

addition and subtraction.

Develop the ability to reason and analyze.

COMMUNICATIVE UNIVERSAL LEARNING ACTIONS.
Participate in dialogue in class, listen and understand the speech of others.
Equipment: textbook “Mathematics” (Author - A.L. Chekin, 1st grade, part 2), printed notebook for independent work No. 2 (Author - O.A. Zakharova), school supplies, fan with numbers,

During the classes:
1. Motivation for educational activities.
a) Greeting;
b) Lesson mood:
The bell rang and stoppedThe lesson begins.Well, check it out, my friend,Are you ready to start the lesson? Is everything in place? Is everything alright?Pen, book and notebooks (2)?
Is everyone sitting correctly?Is everyone watching carefully?
2. Update background knowledge.
a) Oral counting (Teacher reads assignments)
1.Game “Distribute the numbers into the house”
Using the numbers from this series, distribute them into cells so that their sum is equal to the house number. In order not to forget which numbers were distributed to neighboring apartments, you need to mark them with arrows.
1 2 3 4 5 5 6 7 8 9 + (House with the number 10 on the roof)

We played with you and fixed the composition of the number 10.-What interesting things did you notice when distributing numbers into adjacent cells?(Adjacent cells contain numbers that are in the same places on the left and right)You are very attentive! I share your point of view!
3. Report the topic of the lesson.
What topic will we study today? (pause) -Subtract single digit numbers from 10. Where can we find out what we have studied and what remains to be studied? (you need to refer to the contents of the textbook)
Teacher: Open the textbook on the page where the new topic is located,READ THE TOPIC TITLE.Why do you need to be able to subtract single-digit numbers from 10?
Look carefully, where should we start?

4. Studying new material. Work from the textbook (p. 48).
Task No. 1. Find and write down in your notebook all the differences in which the minuend is equal to 10. 10 – 5 15 - 10 10 - 3 9 - 4 10 – 1 10 - 2 (pay attention to conventional signs to the task)-What are they talking about? (Think)
-We will work in pairs. Agree which of you reads and which listens so that you can complete the task without errors.
-Read the first part of the task.
-Find and write down in your notebook all the differences in which the minuend is equal to 10.

10-5 10-3 10-1 10-2 Voice your differences?
- Let's analyze the proposed differences.-How are they similar?
(The minuend is 10, and the subtrahend is a single digit number)
-Calculate and write down the values ​​of these differences in your notebook, using your knowledge of the composition of the number 10.Checking the difference values ​​using a fan.
-Perfect! You are on the right track.
Read task No. 2 to yourself. Write down the differences in your notebook. Find and write down the values ​​of the indicated differences using the "Addition Table" 10 – 8 10 - 5 10 – 3 10 - 6 10 – 2 10 – 4 10 – 9 10 – 7 10 – 1
-What does the author of the textbook advise us? Where can I see the “Addition Table”? (Textbook flyleaf)
Children work independently. (Check by row, chain)
-Why were you recommended to use the “Addition Table”, since we were doing subtraction?-Have you noticed the connection between addition and subtraction?-What rule did you use?- Let's repeat in chorus! (If we subtract the known term from the sum, we get another (unknown) term.
Well done! You did a great job analyzing the addition table!
-Summarize. -So, what are we learning in class? (subtract single-digit numbers from 10)-Children who understand how to subtract single-digit numbers from 10(Based on knowledge of the composition of the number and using the “Addition Table”)
1 physical minute (Students do the exercise, repeating the words and corresponding movements after the teacher)
Our rest is a physical education minute.Take your seats:Step in place left, right,One and two! One and two!Keep your back straight,One and two! One and two!And don't look at your feet,One and two! One and two!CHECKING PRIMARY PERCEPTIONIndependentwork in a printed notebook. Page 80 (task No. 1, peer review)-Children, I’ll give you a hint; it’s more convenient to count along a horizontal line.
1 + 9= 10 – 9 = 10 – 1 = 2 + 8 = 10 – 8 = 10 – 2 = 3 + 7 = 10 - 7 = 10 – 3 = 4 + 6= 10 – 6 = 10 – 4 = 5 +5 = 10 – 5 = 10 – 0 =
-Check your values? What pattern did you see?(Subtraction and addition are interrelated)AMAZING! YOU'RE RIGHT!
WORK FROM THE TEXTBOOK, task No. 3, p. 48 Task. There were 10 sheep grazing on the lawn. Of these, 3 are black and the rest are white. How many white sheep were grazing on the lawn?Solve the problem in your notebook. Calculate and write down the answer.
-Read the text for the third task of the textbook in a low voice.-Can this text be called a task?-How did you manage to recognize the problem?

State the condition of this problem. ( There were 10 sheep grazing on the lawn, of which 3 black, the rest white)
-Formulate a requirement? (How many white sheep were grazing in the meadow?)-What does it mean to solve a problem? (Choose the correct action).-Solve the problem in your notebook. Calculate and write down the answer.
(One child writes the solution to the problem on the board).. Solution:10-3=7(s)
Answer: 7 white sheep were grazing on the lawn.
-If it’s difficult for you to solve a problem, then imagine that out of 10 sheepthree blacks were taken home and only the whites were left to graze.
-Was your new knowledge useful in solving this problem?
Congratulations, you are on the right track!
Physical exercise 2 (Students perform the exercise, repeating words and corresponding movements after the teacher)(Curious Varvara looks left, looks right.
And then he looks down, his neck muscles tense.. Coming back, relaxation is nice.
And then he will look up, above everyone and further than everyone.
Comes back, relaxation is nice.)
WORK IN PRINTED NOTEBOOK No. 2, p.80, task 2Complete the text of the problem according to the diagram. Solve the problem. Calculate and write down the answer. In two vases. . sweets How many candies are in a large vase if there are 4 candies in a small vase?
(children work in pairs, additional task).
What help does the author offer us in solving the problem?(The author proposes a diagram with circles and arcs)

Lesson summary. 3. There were 10 books on the shelf. How many books were taken if there were 7 books, 5 books, 9 books, 4 books, 1 book, 8 books, 2 books, 6 books left?
(students point on fans)
Was

-What did you learn in the lesson?-How can you subtract single-digit numbers from 10?(Remember the composition of the number 10 and learn the “Addition Table”)
Reflection. There is a sun and a cloud on your tables. I will ask you to
When you left class for recess, you pinned on the board: sunshine,
if today's lesson was interesting to you and you had a good
mood, or a cloud, if you were bored in class and had
Bad mood.
Lesson topic:“Subtracting a single digit number from 10.”

Item: mathematics Class: 1

Snetkova Anna Sergeevna, primary school teacher of the first category, Municipal Educational Institution "Likhoslavl Secondary School No. 2", Likhoslavl.

Lesson summary

Lesson Objectives:

Subject information: consider the method of subtracting single-digit numbers from ten based on the composition of the number and the addition table; improve the ability to establish connections between the operations of addition and subtraction; create conditions for consolidating the learned techniques of addition and subtraction within 10; problem solving skills;

Activity and communication: contribute to the formation of the competence of personal self-improvement, communicative competence (work in pairs, in a group); activation cognitive activity learn by using information technologies; develop the ability to reason and analyze.

Value-oriented: creating a favorable emotional environment in the classroom, increasing interest in learning mathematics. Foster a culture of behavior when working frontally, individual work. Learn to use acquired knowledge.

Lesson type: combined (activity method technology).

Forms of work: frontal, individual, personality-oriented tasks.

Equipment: cards with tasks for individual and group work, computer presentation with tasks.

Expected results:

Subject:

Know the composition of the number 10. Know the method of subtracting single-digit numbers from ten based on the composition of the number and the addition table. Be able to establish connections between the operations of addition and subtraction

Personal:
Be able to conduct self-assessment based on the criterion of success of educational activities.

Metasubject:

So how much is it all

Along the forest path

Hurrying to school bunnies in the spring?
Seven tits sat on a branch

Three more arrived to join them.

Count quickly, kids.

How many birds are sitting on the branch?

4 . Preparing to introduce the topic of the lesson. Children setting lesson goals and objectives. (slide 9 - 10)
1) Look at the pictures on the board and make up mathematical expressions based on them.
10 – 3 10 – 6

What are the names of these records? (differences)

What are numbers called when subtracting? Compare the resulting differences. How are they similar?

What is the topic of the lesson? What are our tasks for the lesson? Guess what we will do today?

What knowledge and skills do we need in the classroom?
2) Repeat the composition of the number 10. (slide 11)

Based on the fact that we need to know the composition of the number 10 for calculations, we will now repeat it with you
5. Implementation of the set goals and objectives of the lesson
1 ) Working with the textbook p. 65 No. 1

Analyze the proposed differences. Name those in which the minuend is equal to 10. Write down and find the values ​​of the differences we have chosen. Prove the correctness of your choice. Why don't we use all the expressions?

(work at the board and in a notebook based on the composition of the number and using the appropriate cases of addition)
5 + 5 = 10 Which rule did you use? (If one term is subtracted from the sum,

10 – 5 = 5 then we get another term.)

6. Physical education minute (slide 12)

7. Stage of consolidation of knowledge.

1) Working with the textbook. With. 65 No. 2 Find the value of these differences based on the composition of the number 10.

1 – column at the board. 2 – column – 1 row 3 – column – 2 row.

Examination.

2) Work in a printed notebook p. 92

Independent work with verification.

3) Work in pairs. There are pieces of paper on the table with the amount written down. Find its value and make two differences based on it.

Example: 6 + 4 = 10

4) Solving expressions by groups. Focus on success. Control(multi-level tasks) Each student can perform those calculations that he is able to do.

– The little squirrel has prepared an interesting task for you.

– Each row has examples. Each of you must solve the example, write down the answer and pass the paper to the other along the chain. You have the right to correct another's mistake if you find it.

8. Summing up stage. (slide 16)

1) – Our journey ends and we will check how you worked today. What topic were we working on? What were our goals? Have we achieved them?

 Do I need to know this?

- Where can this be useful? (slide 17)

Game "Shop"

Look carefully at the board and from the proposed items, choose only those that you can buy with 10 rubles. Calculate how much change the seller should give you.
2) Reflection.

The lesson is useful, everything is clear.

There are just some things that are a little unclear.

You still have to work hard.

Yes, it’s still difficult to study!

- Thank you for your work.

Presentation

Subtract means to take one number away from another.

Subtraction is an action in which a smaller number is taken away from a larger one. When subtracting integers, the larger number is reduced by as many units as the smaller number contains. Subtracting one number from another means reduce one number to another, so subtraction is inverse action of addition.

In subtraction, the two given numbers are called minuendable and subtractable , and the required - difference .

The minuend is a larger number from which another is subtracted. It decreases by subtraction.

A subtrahend is a smaller number that is subtracted from a larger one.

The difference is the output obtained from the subtraction. The difference determines why one number is greater than another or shows the difference between two numbers.

Subtraction sign. The subtraction action is indicated by a - (minus) sign.

Subtracting single digit numbers

To indicate that 6 must be subtracted from 9, write these numbers side by side, separating them with a - (minus) sign:

The difference between these numbers will be 3, and the progress of the calculation is expressed verbally:

nine minus six equals three.

In writing:

The larger number 9 will be the minuend, the smaller number 6 will be the subtrahend, and the number 3 will be the remainder.

Subtraction methods

There are two ways to subtract one number from another:

or you can subtract from the larger number as many units as are contained in the smaller number. So, subtracting 6 from 9 means subtracting 6 from 9. The number 3 will be the required remainder;

or you can add one to a smaller number until you get a larger number. So, subtracting 6 from 9, we add 3 units to 6. The number of units that must be added to the smaller number to make it equal to the larger number determines the difference. A smaller number with a difference must be equal to a larger number, therefore, the smaller number and the difference are terms, and the larger one is their sum. Based on this another definition of subtraction:

Subtraction is an action in which, given a given sum and one term, another term is found.

In this case this sum is the minuend, this term is the subtrahend, and the claimand I difference- another term.

Subtracting multi-digit numbers

Subtraction multi-digit numbers is based on the property of numbers by which subtracting a number is the same as subtracting all its parts. From this property it is clear that subtracting a number is the same as subtracting sequentially all its units, tens, hundreds, etc. To indicate that from the number 7228 you need to subtract 3517, write:

and subtract separately units from units, tens from tens, etc.

To make subtraction easier, sign the smaller number under the larger one so that units of the same orders are in the same vertical column, draw a line, put a subtraction sign on the left - and sign the difference under the line.

The progress of the calculation is expressed verbally:

Let's start subtraction with simple units: 8 without 7 is 1; sign under units 1.

Subtract tens: 2 without 1 gives 1, we sign 1 under the tens.

Subtract hundreds. Five cannot be subtracted from 2, so we take one from the next highest order (thousands), which we denote by putting a dot over 7. A unit of each order contains 10 units of the next lower order. Adding these 10 units to 2, we get 12; 12 without 5 makes 7, we sign 7 under the hundreds. When they borrow one from a higher order, they signify this by placing a dot over the order from which they borrow.

Let's subtract thousands. Instead of 7 thousand, only 6 thousand remained, for one was taken. 6 without 3 makes 3; sign under 3 thousand.

The progress of the calculation is expressed in writing:

Example. Subtract 6025 from 17004.

You cannot subtract 5 from 4. We borrow one from tens, the next highest order, but in this order there are no units; we borrow from hundreds, and there are no hundreds; we borrow from thousands and denote this with a dot above the number 7.

A unit of the fourth order has 10 units of the third order. Taking one of them for tens, we leave them in hundreds as only 9. By adding 10 to 4, we have 14.

By subtraction, we get:

for units 14 - 5 = 9

for tens 9 - 2 = 7

for hundreds 9 - 0 = 9

for thousands 6 - 6 = 0

For tens of thousands we have 1, because this figure of the minuend is transferred to the difference without change.

The progress of the calculation will be expressed in writing:

From the previous examples we deduce subtraction rules:

To subtract integers, you need to sign the subtrahend under the minuend so that units of the same order are in the same vertical column, draw a line under which you sign the difference.

Subtraction must begin with simple units, that is, from the first column, and then, moving to the next columns from right hand to the left, subtract tens from tens, hundreds from hundreds, etc.

If the number of the subtracted is less than the number of the reduced, the difference is signed in the same column; if the numbers are equal, the difference will be zero. If the digit of the subtracted is greater than the corresponding digit of the minuend, they take one from the next order of the minuend, marking this with a dot placed above the digit from which they borrow, apply 10 to the digit of the minuend and perform the subtraction. A number with a dot is counted one less.

If, during subtraction, the digit of the minuend from which one borrows is 0, followed by zeros in the minuend, then borrow from the first significant digit, placing dots over it and all intermediate zeros. A digit with a dot is counted as one less, and zeros with a dot are counted as 9.

Subtraction continues until the full difference is obtained.

The extra digits of the minuend are transferred to the difference.

Dependence between the data and the required subtraction

From example 9 - 6 = 3 it is clear that

The minuend is equal to the subtrahend added with the difference: 9 = 6 + 3.

The subtrahend is equal to the minuend without a difference: 6 = 9 - 3.

The difference is equal to the minuend without the subtrahend: 3 = 9 - 6.

Arithmetic addition. The difference between a number and the nearest higher unit is called arithmetic complement. So, the arithmetic complements of the numbers 7, 79, 983 are the following numbers:

10 - 7 = 3
100 - 79 = 21
1000 - 983 = 17

Arithmetic's complement is sometimes used to make arithmetic calculations easier.

Topic: subtracting single digit numbers from 10.

Lesson type : combined

Forms of work

Equipment:

Expected results:

Subject:

Personal:

Metasubject:

Form UUD:

Personal: the ability to self-assess based on the criterion of success in educational activities.

Regulatory UUD: the ability to determine and formulate a goal in a lesson with the help of a teacher; pronounce the sequence of actions in the lesson; work according to a collectively drawn up plan; evaluate the correctness of the action at the level of adequate assessment; plan your action in accordance with the task; make the necessary adjustments to the action after its completion based on its assessment and taking into account the nature of the errors made; express your guess.

Communicative UUD: the ability to express one’s thoughts orally; listen and understand the speech of others; jointly agree on the rules of behavior and communication in the lesson and follow them.

Cognitive UUD: the ability to navigate one’s knowledge system: distinguish new things from what is already known with the help of a teacher; acquire new knowledge: find answers to questions using a textbook, your life experience and information received in class.

Lesson plan:

1. Organizational moment.

7. Physical education minute.

11. Lesson summary.

12. Reflection.

1. Organizational moment.

The bell rang loudly.

Is everything in place, is everything okay?

Book, pen and notebooks?

Slide

5,1,4,2,3,0,9,7,12,11

Slide

0 1 2 3 4 5 7 9 11 12

We've worked with numbers, now let's count.

(Number chains)

What unusual thing did you notice?

Slide

10 – 3 10 – 6

(Knowledge of the composition of the number 10)

Open your notebooks

1

We comment from the spot.

5 + 5 = 10 Which rule did you use? (If one term is subtracted from the sum,

10 – 5 = 5 then we get another term.)

6. Physical education minute (slide)

7. Stage of consolidation of knowledge.

1) Working with the textbook. With. 65 No. 2 Find the value of these differences based on the “Addition Table”. Where can I find it?

We work in rows. We check with a consultant. Assess using traffic lights. Why were you recommended to use the “Addition Table” because we subtracted? What rule did you use?

Working with the textbook p. 65 No. 3 Read the text for the third task in a low voice. What is this text called? What does each task contain? State the condition of this problem. State your requirement. What does it mean to solve a problem?

Decide for yourself. One at the board.

Fizminutka

2) Work in a printed notebook p. 92

Independent work with verification.

3) Work in pairs. There are pieces of paper on the table with the amount written down. Find its value and make two differences based on it.

Example: 6 + 4 = 10

10 – 6 = 4

10 – 4 = 6

4) Solving expressions by groups. Focus on success. Control (multi-level tasks) Each student can perform those calculations that he is able to do.

– Each row has examples. Each of you must solve the example, write down the answer and pass the piece of paper to the other along the chain. You have the right to correct another's mistake if you find it.

8. Summing up stage. (slide)

1) Our lesson ends and we will check how you worked today. What topic were we working on? What were our goals? Have we achieved them?

Do you need to know this?

Where can this be useful?(slide)

Game "Shop"

Look carefully at the board and from the proposed items, select only those that you can buy with 10 rubles. Calculate how much change the seller should give you.

2) Reflection.

Was it easy for you or were there difficulties?

What did you do best and without mistakes?

Which task was the most interesting and why?

Your self-esteem coincides with mine.

View document contents
“UMK pnsh 1st grade “Subtracting single-digit numbers from 10””

Topic: Subtracting single digit numbers from 10.

Lesson type : combined

Forms of work : frontal, individual, personality-oriented tasks.

Equipment: cards with tasks for individual and group work, computer presentation with tasks.

Expected results:

Subject:

Know the composition of the number 10. Know the method of subtracting single-digit numbers from ten based on the composition of the number and the addition table. Be able to establish connections between the operations of addition and subtraction

Personal:
Be able to conduct self-assessment based on the criterion of success of educational activities.

Metasubject:

Be able to determine and formulate a goal in a lesson with the help of a teacher; pronounce the sequence of actions in the lesson; express your assumption (Regulatory UUD).

Be able to express your thoughts orally; listen and understand the speech of others; jointly agree on the rules of behavior and communication in the lesson and follow them (Communicative UUD).

Be able to navigate your knowledge system: distinguish new from already known with the help of a teacher; gain new knowledge: find answers to questions using the textbook, your life experience and information received in the lesson (Cognitive UUD).

Form UUD:

- Personal : ability for self-assessment based on the criterion of success in educational activities.

- Regulatory UUD : the ability to determine and formulate a goal in a lesson with the help of a teacher; pronounce the sequence of actions in the lesson; work according to a collectively drawn up plan; evaluate the correctness of the action at the level of adequate assessment; plan your action in accordance with the task; make the necessary adjustments to the action after its completion based on its assessment and taking into account the nature of the errors made; express your guess.

- Communication UUD: the ability to express one’s thoughts orally; listen and understand the speech of others; jointly agree on the rules of behavior and communication in the lesson and follow them.

- Cognitive UUD: the ability to navigate one’s knowledge system: distinguish new things from what is already known with the help of a teacher; gain new knowledge: find answers to questions using the textbook, your life experience and information received in the lesson.

Lesson plan:

1. Organizational moment.

2. Motivation for educational activities.

3. Preparation for the main educational and cognitive activities.

4. Updating of basic knowledge. Verbal counting.

5. Preparing to introduce the topic of the lesson. Goal setting. Children setting lesson goals and objectives.

6. Implementation of the set goals and objectives of the lesson

7. Physical education minute.

8. Reinforcing the material covered

9. Independent work of students

10. Checking the mastery of the material.

11. Lesson summary.

12. Reflection.

1. Organizational moment.

The bell rang loudly.

Check if you are ready to start the lesson

Everything is in place, is everything okay?

Book, pen and notebooks?

Have you checked? Sit down. Work hard!

Today we will have a math lesson with our guests. Work actively and don't be afraid!

Let's start our work with mental calculation.

1.Rank the numbers in ascending order.

Slide

5,1,4,2,3,0,9,7,12 ,11

Slide

0 1 2 3 4 5 7 9 11 12

What numbers are missing?(6 8 10)

What two groups can the number series be divided into?

We've worked with numbers, now let's count.

(Number chains)

What arithmetic operations did you perform?

What unusual thing did you notice?

Describe the number 10.

How can you get the number 10? (Composition of numbers) slide

Based on the composition of the number 10, solve the problem

Show the answer using a fan

4. Preparation for introducing the lesson topic. Children setting lesson goals and objectives. (slide

1) Look at the pictures and make up mathematical expressions based on them.

Slide

10 – 3 10 – 6

What are the names of these records? (differences)

What are numbers called when subtracting? Compare the resulting differences. How are they similar?

What is the topic of the lesson? What tasks will we set for ourselves in class? Guess what we will do today?

What knowledge and skills will we need in the lesson?

(Knowledge of the composition of the number 10)

5. Implementation of the set goals and objectives of the lesson

Open your notebooks

What day of the week is it today? Month? Number? (Characteristic) Write down

1 ) Working with the textbook p. 65 No. 1

Analyze the proposed differences. Name those in which the minuend is equal to 10. Write down and find the values ​​of the differences we have chosen. Prove the correctness of your choice. Why don't we use all the expressions?

On this lesson you will learn to add and subtract single-digit numbers using place value. By solving interesting problems, you will study the algorithm for adding and subtracting numbers by passing through ten and get acquainted with the table for adding single-digit numbers up to 20. You will have the opportunity to practice the previously studied material using interesting examples.

Subject:Introduction to basic concepts in mathematics

Lesson: Adding and subtracting single-digit numbers using place value. Addition table up to 20

Using a graphical model, you can explain addition of single-digit numbers passing through tens.

How can you add 9 and 7?(Fig. 1)

Rice. 1

The graphical model shows that the first term 9 must be added to 10. To do this, we divide the second term into two parts, one of which is equal to the number 1, since

9 + 1 = 10, which means 7 = 1 + 6. (Fig. 2)

Rice. 2

Let's do the addition by parts:

9 + 7 = (9 + 1) + 6 = 10 + 6 = 16

Answer: 9 + 7 = 16.

You can add these numbers differently. (Fig. 3)

Rice. 3

The second term 7 can be added to 10. To do this, we divide the first term into two parts, one of which is equal to the number 3. Therefore, 9 = 3 + 6.

Rice. 4

Let's do the addition by parts:

7 + 9 = (7 + 3) + 6 = 10 + 6 = 16

The first term is 9, it lacks one unit to 10, so we break the second term into parts. 5 is 1 and 4. We add to 9 first one unit, and then the remaining four units.

9 + 5 = 9 + (1 + 4) = 14

The first term is 6, it lacks up to 10 four units, so we divide the second term into parts: 4 and 2. We add 4 to 6 first and get ten units, and then the remaining two units.

6 + 6 = 6 + (4 + 2) = 12

The first term is 4, it lacks up to 10 six, so we divide the second term 8 into parts: 6 and 2. We first add six units to 4 and get ten units, and then the remaining two units.

4 + 8 = 4 + (6 + 2) = 12

In the minuend 15 there are five units, so we divide the subtracted 7 into parts: 5 and 2. We first subtract five units from 15, we get 10. Then we subtract the remaining two units from ten.

15 - 7 = 15 - (5 + 2) = 8

In the minuend 16 there are six units, so we divide the subtracted 9 into parts: 6 and 3. First we subtract six units from 16, we get 10. And then from 10 we subtract the remaining three units.

16 - 9 = 16 - (6 + 3) = 7

In the minuend 12 there are two units, so we divide the subtracted 4 into parts: 2 and 2. From 12 we subtract 2, we get 10. And from 10 we subtract 2.

12 - 4 = 12 - (2 + 2) = 8

Answer: 12 - 4 = 8.

Using the technique of addition and subtraction by parts with passing through ten is not always convenient, so you need to learn table for adding single digit numbers up to 20 by heart.

The figure shows a table that will make it easier for you to learn cases of adding single-digit numbers up to 20. (Fig. 7)

Rice. 7

In each column, the first term is the same, and the second increases by one, which means the sum will also increase by one. Let's find the value of these amounts.

9 + 2 = 11, therefore: 9 + 3 = 12, reasoning this way, we fill out the entire table. (Fig. 8)

Rice. 8

Each line contains amounts with the same answers. Choose the way it will be easier for you to remember the answers: by columns or by rows. If you learn the table for adding single-digit numbers up to 20 well, then it will not be difficult for you to subtract single-digit numbers within 20.

Bibliography

1. Alexandrova L.A., Mordkovich A.G. Mathematics 1st grade. - M: Mnemosyne, 2012.
2. Bashmakov M.I., Nefedova M.G. Mathematics. 1 class. - M: Astrel, 2012.
3. Bedenko M.V. Mathematics. 1 class. - M7: Russian word, 2012.

1. Social network of educators ().
2. 5klass.net ().
3. Self-taught ().

Homework

1. Remember how to correctly add and subtract single-digit numbers using place value.

2. Help the frog solve the examples.

3. Solve the examples and color the picture.