2 7/8 + (1 3/5 + 1 1/8) =

7 1 / 2 - (1 3/8 + 1 1/2) =

9 1/16 - (5/8 + 7/16) =

7 3/4 + (2 7/8 - 1 3/4) =

1. 1 7/8 + (1 3/5 + 1 1/8) = 5 1/10

1) 1 3/5 + 1 1/8 = 1 24/40 + 1 5/40 = 2 29/40

2) 1 7/8 + 2 29/40 = 1 35/40 + 2 29/40 = 3 + 84/40 =

=3 + 2 4/40 = 5 4/40 = 5 1/10

2. 7 1/2 - (1 3/8+1 1/2) = 4 5/8

1) 1 3/8 + 1 1/2 = 1 3/8 + 1 4/8 = 2 7/8

2) 7 1/2 - 2 7/8 = 7 4/8 - 2 7/8 =

= 60/8 - 23/8 = 37/8 = 4 5/8

3. 9 1/16 - (5/8+7/16) = 8

1) 5/8+7/16 = 10/16 + 7/16 = 17/16 = 1 1/16

2) 9 1/16 - 1 1/16 = 8

4. 7 3/4 + (2 7/8 - 1 3/4) = 8 7/8

1) 2 7/8 - 1 3/4 = 2 7/8 - 1 6/8 = 1 1/8

2) 7 3/4 + 1 1/8 = 7 6/8 + 1 1/8 = 8 7/8