Bài tập 1.  Thực hiện phép tính. 

a) $\frac{3}{7}+\frac{3}{7}:(\frac{−3}{2})−\frac{1}{2}$

b) $2\frac{1}{2}−(−\frac{1}{2})^{2}+\frac{3}{4}$

c) $(\frac{3}{8}−1,25):(\frac{3}{4}−0,25)^{2}$

d) $1\frac{2}{5}:\frac{14}{15}+(1\frac{1}{3}−2\frac{1}{2}):\frac{5}{6}$

Hướng dẫn trả lời.

a) $\frac{3}{7}+\frac{3}{7}:(\frac{−3}{2})−\frac{1}{2}=\frac{3}{7}+\frac{3}{7}.(\frac{−2}{3})−\frac{1}{2}=\frac{3}{7}+(\frac{−2}{7})−\frac{1}{2}=\frac{1}{7}−\frac{1}{2}=\frac{−5}{14}$

b) $2\frac{1}{2}−(−\frac{1}{2})^{2}+\frac{3}{4}= \frac{5}{2}−\frac{1}{4}+\frac{3}{4}=\frac{5}{2}+\frac{1}{2}$=3

c) $(\frac{3}{8}−1,25):(\frac{3}{4}−0,25)^{2}=(\frac{3}{8}−\frac{5}{4}):(\frac{3}{4}−\frac{1}{4})^{2}=(\frac{−7}{8}):(\frac{1}{2})^{2}=\frac{−7}{2}$

d) $1\frac{2}{5}:\frac{14}{15}+(1\frac{1}{3}−2\frac{1}{2}):\frac{5}{6}= \frac{7}{5}.\frac{15}{14}+(\frac{4}{3}−\frac{5}{2}):\frac{5}{6}=\frac{3}{2}+(\frac{−7}{6}:\frac{5}{6})=\frac{1}{10}$