Math 1 Lesson: Subtraction 17

### 1.1. Knowledge to remember

– Know how to do subtraction (don’t remember) within 20

– Mental subtraction form 17 – 3

### 1.2. Maths for Subtraction 17 – 3

**Form 1: Perform calculations of the form**

Perform vertical or horizontal subtraction.

With the vertical calculation, I put the calculation in line and then subtract the numbers from the units to tens.

**Form 2: Mental calculation**

Perform the 17-3 non-memory subtraction in a horizontal row without setting the calculation.

– Step 1: Subtract the numbers in the unit row

– Step 2: Keep the digit 1 in the tens place.

**Form 3: Math Quiz**

Using the subtraction I have just learned, I solve word problems.

– Read and analyze the problem: Determine the given data, the number of reductions and the requirements of the problem.

– Find a solution: To find the remaining value, I often use subtraction.

– Presentation of the solution: Write the solution, calculation and answer to the problem.

– Check the solution of the problem and the result just found.?

### 1.3. Solving Textbook Exercises page 110

**Lesson 1 page 110**

Calculate

**Solution method**

Subtract from right to left.

__Solution guide__

**Lesson 2 page 110**

Calculate:

12 – 1 = 13 – 1 = 14 – 1 =

17 – 5 = 18 – 2 = 19 – 8 =

14 – 0 = 16 – 0 = 18 – 0 =

__Solution method__

Mentally subtract and then fill in the blanks with the result.

__Solution guide__

12 – 1 = 11 13 – 1 = 12 14 – 1 = 13

17 – 5 = 12 18 – 2 = 16 19 – 8 = 11

14 – 0 = 14 16 – 0 = 16 18 – 0 = 18

**Lesson 3 page 110**

Fill in the blanks with appropriate numbers (according to the form):

__Solution method__

Subtract the numbers of the first column from the numbers of the upper row; Write the results in the corresponding box in the lower row.

**Solution guide**

### 1.4. Solve textbook exercises page 111

**Lesson 1 page 111**

Calculate then calculate:

14 – 3 17 – 5 19 – 2

16 – 5 17 – 2 19 – 7

**Solution method**

– Write the calculation so that the numbers in the same row and column are together.

– Subtract from right to left in turn.

__Solution guide__

**Lesson 2 page 111**

Mental arithmetic:

14 – 1 = 15 – 4 = 17 – 2 = 15 – 3 =

15 – 1 = 19 – 8 = 16 – 2 = 15 – 2 =

__Solution method__

Do the math and fill in the blanks.

__Solution guide__

14 – 1 = 13 15 – 4 = 11 17 – 2 = 15 15 – 3 = 12

15 – 1 = 14 19 – 8 = 11 16 – 2 = 14 15 – 2 = 13

**Lesson 3 page 111**

Calculate:

12 + 3 – 1 = 17 – 5 + 2 = 15 – 3 – 1 =

15 + 2 – 1 = 16 – 2 + 1 = 19 – 2 – 5 =

__Solution method__

Count from left to right.

__Solution guide__

12 + 3 – 1 = 14 17 – 5 + 2 = 14 15 – 3 – 1 = 11

15 + 2 – 1 = 16 16 – 2 + 1 = 15 19 – 2 – 5 = 12

**Lesson 4 page 111**

Append (according to the pattern):

__Solution method__

Perform calculations from left to right.

Then match with the correct answer.

**Solution guide**

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