Question

Tính

a) -2/7 x 21/8

b) 0,24 x -15/4

c) (-2) x (-7/12)

d) (-32/25) : 6

Answer 1

a)\(-\frac{2}{7}x\frac{21}{8}=\frac{-2x3x7}{7x4x2}=-\frac{3}{4}\)

b) 0,24 x -15/4=-9/10

c) (-2) x (-7/12)=7/6

d) (-32/25) : 6=-16/75

Answer 2

\(a.\frac{-2}{7}\times\frac{21}{8}=\frac{\left(-2\right)\times21}{7\times8}=\frac{-1\times3}{1\times4}=\frac{-3}{4}.\)

\(b.0,24\times\frac{-15}{4}=\frac{6}{25}\times\frac{\left(-15\right)}{4}=\frac{6\times\left(-15\right)}{25\times4}=\frac{3\times\left(-3\right)}{5\times2}=\frac{-9}{10}\)

\(c.\left(-2\right)\times\frac{\left(-7\right)}{12}=\frac{\left(-2\right)\times\left(-7\right)}{12}=\frac{14}{12}=\frac{7}{6}\)

\(d.\frac{-32}{25}:6=\frac{-32}{25}\times\frac{1}{6}=\frac{-16}{75}\)