Question

Calculeaza in doua moduri:a)7×(2+5); b)6×(9-3); c)5×8+5×10

Answer 1

a ) 7 × ( 2 + 5 )

= 7 × 7

= 49

7 × 2 + 7 × 5 =

= 14 + 7 × 5

= 14 + 35

= 49

b ) 6 × ( 9 - 3 )

= 6 × 6

= 36


6 × 9 - 6 × 3 =


= 54 - 18

= 36


c ) 5 × 8 + 5 × 10 =

40 + 5 × 10 =

= 40 + 50

= 90

5 × ( 8 + 10 ) = 90

Answer 2

a) distributivitatea = ca proprietate a inmultirii
7 x ( 2 + 5) = 7 x 7 = 49  → primul mod 
7 x 2 + 7 x 5 = 14 + 35 = 49 → al doilea mod

b) 
6 x ( 9 - 3) = 6 x 6 = 36 → primul mod ( produs dintre un factor si diferenta)
6 x 9 - 6 x 3 = 54 - 18 = 36 → al doilea mod

c) 
5 × 8 + 5 × 10 = 40 + 50 = 90 → primul mod 
5 x ( 8 + 10) = 5 x 18 = 90 → al doilea mod