Giải thích các bước giải:
$\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{1\frac{1}{6}-0,875+0,7}+\frac{6}{7}$
$=\frac{\frac{91}{273}-\frac{39}{273}-\frac{21}{273}}{\frac{182}{273}-\frac{78}{273}-\frac{42}{273}}.\frac{\frac{1}{3}-0,05}{\frac{7}{6}-0,175}+\frac{6}{7}$
$=\frac{\frac{31}{273}}{\frac{62}{273}}.\frac{\frac{34}{120}}{\frac{119}{120}}+\frac{6}{7}$
$=\frac{1}{2}.\frac{2}{7}+\frac{6}{7}$
$=\frac{2}{14}+\frac{6}{7}$
$=\frac{1}{7}+\frac{6}{7}$
$=1$
Học tốt!!!
