Thực hiện phép tính: a) 0,4 - $\frac{-6}{30}$ b) $\frac{1}{4}-|\frac{-3}{2}+\frac{5}{8}|$
2 câu trả lời
Đáp án+Giải thích các bước giải:
A) 0,4 - $\dfrac{-6}{30}$
= $\dfrac{2}{5}$ - $\dfrac{6}{30}$
= $\dfrac{2x6}{5x6}$ - $\dfrac{6}{30}$
= $\dfrac{12}{30}$ - $\dfrac{6}{30}$
= $\dfrac{12-6}{30}$
= $\dfrac{6}{30}$
= $\dfrac{1}{5}$
b) $\dfrac{1}{4}$ - $|\dfrac{-3}{2}$ + $\dfrac{5}{8}|$
= $\dfrac{1}{4}$ - $|\dfrac{-3x4}{2x2}$ + $\dfrac{5}{8}|$
= $\dfrac{1}{4}$ - $|\dfrac{-12}{8}$ + $\dfrac{5}{8}|$
= $\dfrac{1}{4}$ - $|\dfrac{-12+5}{8}|$
= $\dfrac{1}{4}$ - $|\dfrac{-7}{8}|$
= $\dfrac{1}{4}$ - $\dfrac{7}{8}$
= $\dfrac{1x2}{4x2}$ - $\dfrac{7}{8}$
= $\dfrac{2}{8}$ - $\dfrac{7}{8}$
= $\dfrac{2-7}{8}$
= $\dfrac{-5}{8}$
