Bài 69: trang 36 sgk Toán 6 tập 2
Nhân các phân số (rút gọn nếu có thể):
| a) \(\frac{-1}{4}.\frac{1}{3}\) | b) \(\frac{-2}{5}.\frac{5}{-9}\) | c) \(\frac{-3}{4}.\frac{16}{17}\) |
| d) \(\frac{-8}{3}.\frac{15}{24}\) | e) \((-5).\frac{8}{15}\) | g) \(\frac{-9}{11}.\frac{5}{18}\) |
Bài Làm:
a) \(\frac{-1}{4}.\frac{1}{3}=\frac{-1.1}{4.3}=\frac{-1}{12}\)
b) \(\frac{-2}{5}.\frac{5}{-9}=\frac{-2.5}{5.(-9)}=\frac{2}{9}\)
c) \(\frac{-3}{4}.\frac{16}{17}=\frac{-3.16}{4.17}=\frac{-12}{17}\)
d) \(\frac{-8}{3}.\frac{15}{24}=\frac{-8}{3}.\frac{5}{8}=\frac{-8.5}{3.8}=\frac{-5}{3}\)
e) \((-5).\frac{8}{15}=\frac{-5.8}{15}=\frac{-8}{3}\)
g) \(\frac{-9}{11}.\frac{5}{18}=\frac{-9.5}{11.18}=\frac{-5}{22}\)