#### Introduction:

- In this session, you will learn to solve addition problems using different addition strategies.
- In the previous session, we learned about addition using place value.

ADD 45 + 27

Add ones first.

5 ones + 7 ones= 12

12 has 1ten 2ones.

Now add tens.

4tens + 2tens+ 1ten= 7 tens.

Then add 7tens+ 2ones= 72.

**Q1. Add 18 + 29, draw blocks or open number line to help.**

8 + 9 = _____

10 + 30 = _____

18 + 29 = _____

18 + 29 = ?

8 + 9 = 17

10 + 30 = 40

18 + 29 = 47

**Q2. Shan painted 57 wall paintings. Then he painted 19 modern arts. How many paintings did he paint? Write an addition equation to show the problem.**

57 + 19 = ____

7 + 9 = ___

50 + 10 + ___ = ____

___ + ____ = ____

**Answer:**

57 + 19 = ?

Add ones

7 + 9 = 16

Then add tens.

50 + 10 + 10 = 70

70 + 6 = 76

57 + 19 = 76

**Q3. A chessboard has 32 black squares and 32 white squares.**

How many squares do they have in all? Use any of the strategies

You have used?

Number of black squares = 32

Number of white squares= 32

Total squares. = 32 + 32

Use models and add.

Add tens.

3tens + 3tens= 6tens

Then add-ones

2ones + 2ones= 4ones

6tens + 4ones= 64

**Q4. Find 25 + 19 in different ways.**

25 + 19 = ?

Add ones.

5 ones + 9 ones = 14

14 has 1 ten + 4 ones

Add tens

2 tens + 1 ten + 1 ten = 4 tens

4 tens + 4 ones = 44

So, 25 + 19 = 44

Draw tens and ones and find the answer.

25 + 19 = ?

Add ones.

5 ones + 9 ones = 14

14 has 1 ten and 4 ones

Add tens

2 tens + 1 ten + 1 ten = 4 tens

4 tens + 4 ones = 44

25 + 19 = 44

**Q5. Add 35 + 16 on an open number line.**

16 has 1ten + 6 ones

Add 35 + 10 = 45

45 + 6 = 51

**Q6. Lily Elizabeth has 32 jade stones and 19 ruby stones. How many stones does she have now? Use a number line and add the numbers.**

19 has 1ten 9 ones.

32 + 10 = 42

42+9 = 51

#### Exercise

A. Find each sum. Solve any way you choose. Draw or explain what you did.

- 37 + 10 = _____
- 69 + 8 = _____
- 50 + 32 = _____
- 72 + 19 = _____
- 12 + 28 = ______.
- A baker sells 35 banana muffins and 29 oat muffins. How many muffins did he sell in all?
- Jason has 24 waistcoat and 12 trousers. How many outfits he has now?
- There are 52 birds and 47 animals in the zoo. How many birds and animals are there in total?
- Sam wants to make a necklace. She used 26 pearls and 37 corals. How many beads did she use in all?
- Find the equation the model shows.

#### Concept Map:

#### What We Have Learned

- Solve addition problems using different strategies.

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