Question

9) Utilizá la propiedad distributiva para resolver estos cálculos de forma mental

a) 21 x 3 =

b) 39 x 4 =

c)4 x 102 =

d)5 x 99 =

Answer 1

Respuesta:

$a)21 \times 3 = (20 + 1) \times 3 = 20 \times 3 + 1 \times 3 = 60 + 3 = 63$

$b)39 \times 4 = (40 - 1) \times 4 = 40 \times 4 - 1 \times 4 = 160 - 4 = 156$

$c)4 \times 102 = 4 \times (100 + 2) = 4 \times 100 + 4 \times 2 = 400 + 8 = 408$

$d)5 \times 99 = 5 \times (100 - 1) = 5 \times 100 - 5 \times 1 = 500 - 5 = 495$