Đáp án+Giải thích các bước giải:
i,
$\dfrac{5}{3}+(\dfrac{-2}{7})-(-1,2)$
$=\dfrac{5}{3}-\dfrac{2}{7}+1,2$
$=\dfrac{29}{21}+1,2$
$=\dfrac{271}{105}$
j,
$0,25+\dfrac{3}{5}-(\dfrac{1}{8}-\dfrac{2}{5}+\dfrac{5}{4})$
$=0,25+\dfrac{3}{5}-\dfrac{1}{8}+\dfrac{2}{5}-\dfrac{5}{4}$
$=0,25+0,6-0,125+0,4-1,25$
$=(0,25-1,25)+(0,6+0,4)-0,125$
$=-1+1-0,125$
$=-0,125$