Cho A = $\frac{13}{50} \times (-15.5) - \frac{13}{50} \times 84\frac{1}{2}

Ta có :

A = $\frac{13}{50} \times (- 15.5) - \frac{13}{50} \times 84 \frac{1}{2}$

= $\frac{13}{50} \times$ (-15.5 - 84.5) = $\frac{13}{50} \times$ (-100) = -26

$B = \frac{(- 0.7)^{2} \times (- 0.5)^{3}}{(\frac{- 7}{3})^{3} \times (\frac{3}{2})^{4} \times (- 1)^{5}}$

$= \frac{0.49 \times (- 125)}{\frac{- 343}{27} \times \frac{81}{16} \times (- 1)}$

= $\frac{- 61.25}{\frac{1029}{16}} = - 61.25 / \frac{1029}{16} = \frac{- 245}{4} \times \frac{16}{1029} = \frac{- 20}{21} .$

Như vậy, bạn An đã tính đúng.

Bài tiếp theo: Cho $A = \frac{\frac{-1}{2} -5 \times \frac{3}{2}^{2}}{15\frac{2}{9} + (-\frac{2}{3})^{2}}