Giải câu 2 trang 45 VNEN toán 5 tập 1

a. $\frac{3}{5} - \frac{1}{15}\times \frac{10}{13} = \frac{3}{5} - \frac{10}{195} = \frac{117}{195} - \frac{10}{195}= \frac{107}{195}$

b. $\frac{1}{2} + \frac{3}{8} : \frac{3}{4}= \frac{1}{2}+ \frac{3}{8}\times \frac{4}{3}=\frac{1}{2}+\frac{12}{24}=\frac{12}{24}+\frac{12}{24}=\frac{24}{24}=1$

c. $\left ( \frac{3}{5}-\frac{3}{20} \right )\times \frac{4}{5}= \left ( \frac{12}{20} - \frac{3}{20} \right )\times \frac{4}{5}=\frac{9}{20}\times \frac{4}{5}=\frac{36}{100}$