Question

TÍNH NHANH

1/3 - 1/7 - 1/13           1/3 - 0,25 + 0,2

______________   :    _______________             + 6/7

2/3 - 2/7 - 2/13            7/6 - 0,875 + 0,7

Answer 1

\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}.\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}+\frac{6}{7}\)

\(=\frac{1}{2}.\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{7.\frac{1}{2}.\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}+\frac{6}{7}\)

\(=\frac{1}{2}.\frac{1}{\frac{7}{2}}+\frac{6}{7}=\frac{1}{2}.\frac{2}{7}+\frac{6}{7}=\frac{1}{7}+\frac{6}{7}=1\)