Răspuns:
ex 1
a) ( 72 : 9 + 9 ) × 5 = 85
( 8 + 9 ) × 5 =
17 × 5 = 85
b) ( 7 × 9 - 13 ) : 5 = 10
( 63 - 13 ) : 5 =
50 : 5 = 10
ex 2
a) 7 × 5 : 5 = 7
35 : 5 = 7
b) 42 : 7 × 9 = 54
6 × 9 = 54
c) 85 - 8 × 5 + 20 = 65
85 - 40 + 20 =
45 + 20 = 65
ex 4
80 × ( 4 × 4 - 4 : 4 - 4 × 4 : 4 ) = 880
80 × ( 16 - 1 - 16 : 4 ) =
80 × ( 16 - 1 - 4 ) =
80 × ( 15 - 4 ) =
80 × 11 = 880
ex 3
( 1 + 2 ) × ( 1 + 5 ) = 18
3 × 6 = 18
a = 1 b = 1
( 0 + 2 ) × ( 4 + 5 ) = 18
2 × 9 = 18
a = 0 b = 4
