Đáp án:
Giải thích các bước giải:
i, $$(\frac{-1}{5} + \frac{3}{7}) : \frac{2}{11} + (\frac{-4}{5} + \frac{4}{7}) : \frac{2}{11}
=(\frac{-1}{5} + \frac{3}{7}) × \frac{11}{2} + (\frac{-4}{5} + \frac{4}{7}) × \frac{11}{2}
=(\frac{-1}{5} + \frac{3}{7} - \frac{4}{5} + \frac{4}{7}) × \frac{11}{2}
=0 × \frac{11}{2}
=0$$
a, $1-\frac{1}{2}+2-\frac{2}{3}+3-\frac{3}{4}+4-\frac{1}{4}-3-\frac{1}{3}-2-\frac{1}{2}-1
=(1+2+3+4-3-2-1) - (\frac{1}{2}+\frac{1}{2})-(\frac{2}{3}+\frac{1}{3})-(\frac{3}{4}+\frac{1}{4})
=4-1-1-1
=1$
