Exchange

Review: ( ) ( ) 4 3s Addition: Multiplication: 3+3+3+3 =12 4×3 =12 How many groups? How many in each group? ( ) ( ) Addition: Multiplication: 4 3s 3+3+3+3 =12 4×3 =12

Review: 7+7+7+7+7=35 5×7=35 9+9=18 4×2 2×9=18 3×6 2+2+2+2=8 6+6+6=18 Multiplication Addition 5×7=35 2×9=18 2+2+2+2=8 6+6+6=18

In rows: 3 4s 3×4 In columns 4 3s 4×3 4×3= 3×4

Practice 1: ( )×( )=( )×( ) 5 5 4 4 ( )×( )=( )×( ) 3 8 8 3 Can you find the 2 multiplication number sentences according to the picture? (column or row) ( )×( )=( )×( ) 5 5 4 4 ( )×( )=( )×( ) 3 8 8 3

Practice 2: 2×6 =（ ）×（ ） 6 2 4×8 =（ ）×（ ） 8 4 8 9 （ ）×（ ）= 9×8 Try to find the partner of the number sentence. 2×6 =（ ）×（ ） 6 2 4×8 =（ ）×（ ） 8 4 8 9 （ ）×（ ）= 9×8 △×☆ =（ ）×（ ） ☆ △ 3 7×（ ）= 3 ×（ ） 7

Why do we“exchange”(swap) ? 3+3+3+3+3+3+3+3+3+3 10+10+10 =30 10×3 = 3×10 =30

Practice 3: 2+2+2+2+2+2+2+2+2=( )×( ) =( )×( )=( )+( )= ( ) 3+3+3+3+3+3+3=( )×( ) = ( )×( )=( )+( ) +( )= ( ) 4+4+4+4+4+4+4+4+4+4=( )×( ) = ( )×( )=( )+( ) +( ) +( )= ( ) 9 2 2 9 9 9 18 7 3 3 7 7 7 7 21 10 4 4 10 40 10 10 10 10

What have we learnt today? ( )×( )=( )×( ) 4 5 5 4 3+3+3+3+3+3+3+3+3+3 10+10+10 =30 10×3 = 3×10 =30