Đáp án:
Giải thích các bước giải:
a)
$\dfrac{4}{5}$ - $\dfrac{1}{2}$ + $\dfrac{1}{3}$
= $\dfrac{3}{10}$ + $\dfrac{1}{3}$
= $\dfrac{19}{30}$
b)
$\dfrac{1×2×3×4}{5×6×7×8}$
= $\dfrac{1×2×3×4}{5×2×3×7×2×4}$
= $\dfrac{1}{5 ×7×2}$
= $\dfrac{1}{70}$
c)
$\dfrac{3}{2}$ × $\dfrac{5}{6}$ × $\dfrac{2}{3}$
= $\dfrac{5}{4}$ × $\dfrac{2}{3}$
= $\dfrac{5}{6}$
d)
$\dfrac{4}{9}$ + $\dfrac{3}{5}$ : $\dfrac{2}{3}$ - $\dfrac{1}{4}$
= $\dfrac{4}{9}$ + $\dfrac{9}{10}$ - $\dfrac{1}{4}$
= $\dfrac{4}{9}$ + $\dfrac{13}{20}$
= $\dfrac{197}{180}$
