Giải bài 2 trang 32

Đề bài

Tính:

a) $11\frac{2}{3}+\frac{-5}{6}$

b) $\frac{5}{8}-2\frac{3}{4}$

c) $7\frac{1}{5}.4\frac{5}{9}$

d) $3\frac{4}{7}:\frac{20}{-9}$

Lời giải chi tiết

a) $11\frac{2}{3}+\frac{-5}{6}=\frac{35}{3}+\frac{-5}{6}=\frac{70}{6}+\frac{-5}{6}=\frac{65}{6}$

b) $\frac{5}{8}-2\frac{3}{4}=\frac{5}{8}-\frac{11}{4}=\frac{5}{8}-\frac{22}{8}=\frac{-17}{8}$

c) $7\frac{1}{5}.4\frac{5}{9}=\frac{36}{5}.\frac{41}{9}=\frac{36.41}{5.9}=\frac{164}{5}$

d) $3\frac{4}{7}:\frac{20}{-9}=\frac{25}{7}:\frac{20}{-9}=\frac{25}{7}.\frac{-9}{20}=\frac{-45}{28}$