Question

Calculați dând factorul comun.

a) 7×5-7×3=
b) 2×3+3×8-3=
c)15+15×7=
d)7×9-7=
e)143×81+143×11+143×7+143

Answer 1

a)  7 × 5 - 7 × 3 = 7 × ( 5 - 3 ) = 7 × 2 = 14

b)   2 × 3 + 3 × 8 - 3 = 3 × ( 2 + 8 - 1 ) = 3 × 9 = 27

c)   15 + 15 × 7 = 15 ×  ( 1 + 7 ) = 15 × 8 = 120

d)   7 × 9 - 7 = 7 × ( 9 - 1 ) = 7 × 8 = 56

e)   143 × 81 + 143 × 11 + 143 × 7 + 143 = 14 300

= 143 × ( 81 + 11 + 7 + 1 ) =

= 143 × 100 =

= 14 300