Đáp án:
Giải thích các bước giải:
Câu 1
a)$\frac{5}{6}$ + $\frac{2}{3}$ + $\frac{1}{4}$
= $\frac{3}{2}$ + $\frac{1}{4}$
= $\frac{7}{4}$
Câu 2
$\frac{-15}{8}$ + $\frac{7}{8}$ - 4
= -1 - 4
= -5
Câu 3
$\frac{2}{3}$ + $\frac{1}{3}$ ($\frac{5}{6}$ - $\frac{4}{9}$) : $\frac{7}{12}$
= $\frac{2}{3}$ + $\frac{1}{3}$ . $\frac{7}{18}$ : $\frac{7}{18}$
= $\frac{2}{3}$ + $\frac{7}{54}$ : $\frac{7}{18}$
= $\frac{2}{3}$ + $\frac{1}{3}$
= 1
Câu 4
$\frac{2}{3}$ + $\frac{1}{3}$ ($\frac{5}{6}$ - $\frac{4}{9}$) : $\frac{7}{12}$
= $\frac{2}{3}$ + $\frac{1}{3}$ . $\frac{23}{18}$ : $\frac{7}{12}$
= $\frac{2}{3}$ + $\frac{23}{54}$ : $\frac{7}{12}$
= $\frac{2}{3}$ + $\frac{46}{63}$
= $\frac{88}{63}$
Câu 5
25% :(12,7-13,2)-2$\frac{3}{5}$
= $\frac{1}{4}$ : $\frac{-1}{2}$ - $\frac{13}{5}$
= $\frac{-1}{2}$ - $\frac{13}{5}$
= $\frac{-31{10}$
Câu 6
$\frac{3}{8}$ : ($\frac{1}{2}$ - 1)³ - ($\frac{-2}{3}$)² . $\frac{9}{5}$
= $\frac{3}{8}$ : ($\frac{-1}{8}$ - $\frac{4}{9}$) . $\frac{9}{5}$
= $\frac{3}{8}$ : $\frac{-41}{72}$ . $\frac{9}{5}$
= $\frac{-27}{41}$ . $\frac{9}{5}$
= $\frac{-243}{205}$
