B1 : Tính a. -3/4 × 12/-5 b. 3^3 ×2 -3 × 4^2 c. 1/3 × 2/5 - 4/3 ÷ 2/5 + 3 d. 2 ÷ ( 1/2 - 2/3 )^2 e. 2/3 × 4/7 + 2/3 × 10/7 - 2/3

Đáp án:

a. $\frac{-3}{4}$ x $\frac{12}{-5}$ = $\frac{-36}{20}$ = $\frac{9}{5}$ 

b. 3³x 2-3 x 4²=27 x 2 -3 x 16 = 54-48=6

c.$\frac{1}{3}$ x $\frac{2}{5}$ -$\frac{4}{3}$ : $\frac{2}{5}$ +3 =$\frac{2}{15}$ - $\frac{20}{6}$ + 3 =$\frac{2}{15}$ - $\frac{50}{15}$ + $\frac{45}{15}$ =$\frac{-1}{15}$ 

d.2 : ($\frac{1}{2}$ - $\frac{2}{3}$ )²

=2 : $\frac{2}{4}$ - $\frac{4}{9}$ 

= $\frac{32}{9}$ 

e. $\frac{2}{3}$ x $\frac{4}{7}$ + $\frac{2}{3}$ x $\frac{10}{7}$ -$\frac{2}{3}$ 

 =$\frac{2}{3}$ x ( $\frac{4}{7}$ + $\frac{10}{7}$ ) =$\frac{2}{3}$ x 2 = $\frac{4}{3}$ 

5sao và ctlhn