## Key Concepts

- Add numbers using place value.
- Use properties of operation to find the sum.
- Solve few model questions related to addition by using place

### Introduction

**Example 1:**

3 – 2 = 1.

Find 2 + ____ = 3

**Solution:**

3 – 2 = 1.

So, 2 + 1 = 3.

## Use addition fact to subtract

**Example 2:**

Find 5 – 3.

To find 5 – 3, you can think:

The missing number is the same in both equations.

You know the addition fact.

3 + 2 = 5

You also know the subtraction fact.

5 – 3 = 2

**Example 3:**

Find 15 – 4.

To find 15 – 4, you can think:

The missing number is the same in both equations.

You know the addition fact.

4 + 11 = 15

You also know the subtraction fact.

15 – 4 = 11

### Make a 10 to Subtract

**Example 4:**

Find how many more balls are needed to be added to make a ten?

**Solution:**

Add 2 more balls to make a ten.

### Use the ten frames to make a 10 to subtract

**Example 5:**

Find 12 – 9

**Solution:**

10 + 2 = 12

### Use the ten frames to make a 10 to subtract (Another way)

**Example 6**:

Find 12 – 9

**Solution:**

10 – 7 = 3

## Exercise

- Think addition and subtract,

6 – 4 =?

4 + ____ = 6

So, 6 – 4 = ____

- Think addition and subtract,

9 – 3 =?

3 + ____ = 9

So, 9 – 3 = ____

- Think addition and subtract,

12 – 4 =?

4 + ____ = 12

So, 12 – 4 = ____

- Complete the addition fact and subtract,

17 – 7 = ____

7 + ____ = 17

- Complete the addition fact and subtract,

14 – 8 = ____

8 + ____ = 14

- Make a ten to subtract by using counters and your workmate.

11

– 4

______

- Make a ten to subtract by using counters and your workmate.

16

– 9

______

- Chen had 13 animal stickers. He gave 5 of the stickers away. How many animal stickers does Chen have now?
- Angie bought 13 strawberries. She ate 8 of the strawberries. How many strawberries does Angie have now?

### Concept Map

### What we have learned

- Use addition fact and subtract two numbers.
- Use the ten frames to make a 10 and subtract two numbers.