Tính a) 3/4 + 7/8 = ..... b) 4/5 - 3/7 = ..... c) 4/5 * 3/8 = ..... d) 12/10 - 3/5 : 2/3

* Hướng dẫn giải

$\begin{array}{l}a)\frac{3}{4}+\frac{7}{8}=\frac{6}{8}+\frac{7}{8}=\frac{13}{8}\\ b)\frac{4}{5}-\frac{3}{7}=\frac{28}{35}-\frac{15}{35}=\frac{13}{35}\\ c)\frac{4}{5}\times \frac{3}{8}=\frac{12}{40}=\frac{3}{10}\\ d)\frac{12}{10}-\frac{3}{5}:\frac{2}{3}=\frac{12}{10}-\frac{3}{5}\times \frac{3}{2}=\frac{12}{10}-\frac{9}{10}=\frac{3}{10}\end{array}$