Giải thích các bước giải:
a)$\frac{-5}{6}$ .$\frac{12}{7}$ .$\frac{-21}{15}$
= $\frac{-5.12.(-21)}{6.7.15}$
=$\frac{1260}{630}$ =2
b) $\frac{1}{6}$ .$\frac{9}{-9}$ .$\frac{-12}{11}$
=$\frac{1}{6}$ .(-1) .$\frac{-12}{11}$
$\frac{1.(-1).(-12)}{6.11}$
=$\frac{12}{66}$ =$\frac{2}{11}$
c) ($\frac{17}{18}$ : $\frac{51}{36}$ ).$\frac{3}{5}$
=$\frac{2}{3}$ .$\frac{3}{5}$
=$\frac{2}{5}$
d) ($\frac{1}{7}$ )$^{2}$ .7$^{2}$
=$\frac{1}{49}$ .49=1
e) (0.125)$^{3}$ .512
=($\frac{1}{8}$ )$^{3}$ .512
=$\frac{1}{512}$ .512=1
f) (0.25)$^{4}$ .1024
=1/256.1024=4