Question

Efetue as multiplicaçoes indocafas uasndo a tecnica so cancelamento quabto possível.
a) 1/3×(-4/7)
b) -3/5×(-5/9)
c) -9/8×4/45
d) +11,25×(+8/9


​

Answer 1

Resposta:

$\frac{1}{3} \times ( - \frac{4}{7} ) \\ \\ - \frac{1}{3} \times \frac{4}{7} \\ \\ - \frac{1 \times 4}{3 \times 7} \\ \\ - \frac{4}{21}$

$b) \: - \frac{3}{5} \times ( - \frac{5}{9} ) \\ \\ \frac{3}{5} \times \frac{5}{9}$

Cancelamos o fator comum 5:

$3 \times \frac{1}{9}$

Cancelamos o fator comum 3:

$\frac{1}{3}$

$c) \: - \frac{9}{8} \times \frac{4}{45}$

Cancelamos o fator comum 9:

$- \frac{1}{8} \times \frac{4}{5}$

Cancelamos o fator comum 4:

$- \frac{1}{2} \times \frac{1}{5} \\ \\ - \frac{1}{10}$

$d) \: 11.25 \times \frac{8}{9} \\ \\ \frac{1125}{100} \times \frac{8}{9} \\ \\ \frac{45}{4} \times \frac{8}{9}$

Cancelamos o fator comum 9:

$\frac{5}{4} \times 8$

Cancelamos o fator comum 4:

$5 \times 2 = 10$