1. Review Rewrite the sentences 5×7=35 7+7+7+7+7=35 2×9=18 9+9=18
Multiplication
=35
Multiplication
2×9=18
9+9=18
Addition
6+6+6=18
3×6=18
4×4=16
Addition
=16

2. In focus The vertical direction: 3 columns, 4 in each column.
3×4 = = 12
The horizontal direction:
4 rows, 3 in each row.
4×3 = = 12

3. Let’s learn
3 columns
4 rows
3×4 =12
4×3 =12
4 in each column
3 in each row
3×4 = 4×3
Exchange the position of two factors, the product is same.

4. Exchange

5. Describe the situation with addition or multiplication.

6. Describe the situation with addition or multiplication.
( ) columns， ( ) in each column.
Addition：
=16
Multiplication ：
8×2=
=16

7. Describe the situation with addition or multiplication.
( ) rows， ( ) in each row.
Addition：
8+8=16
Multiplication ：
2×8=
8+8=16

8. =16
8×2=16
8+8=16
2×8=16
=8×2=2×8=8+8=16

9. Circle and fill in different way : How many stars in the picture？
7×2= =14
2×7=7+7=14 =
7×2=
2×7=
7+7 = 14

10. 2+2+2+2+2+2+2+2=8×2=2×8=8+8=16 2+2+2+2+2+2+2=7×2=2×7=7+7=14
Which addition is handy?
=8×2=2×8=8+8=16
Repeated 7 times
Repeated one more time
=7×2=2×7=7+7=14
Repeated 6 times
Repeated one more time
What’s the purpose to learn Exchange?
Using Exchange can solve what problem?

11. Guided Practice 2+2+2+2+2+2+2+2+2= 3+3+3+3+3+3+3= 4+4+4+4+4+4= = + 9 2× = + 9 2 18 7 3 21 = = + + × × = 6 4 24 × = = + + + × =

12. Write 2 multiplications according to the picture.
3×5=15
2×3=6
5×3=15
3×2=6

13. Challge
If I give you 12 circles, can you arrange them in 2 different ways and write the exchange sentences.
□×□=□×□