`i) (-1/5+ 3/7): 2/11+ (-4/5+ 4/7): 2/11` Tihs hợp lí `a) 1- 1/2+ 2- 2/3+ 3- 3/4+ 4- 1/4- 3- 1/3- 2- 1/2- 1`

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$