Ответ:
- 1)
- \(\frac{7}{16}\cdot\frac{8}{21}=\frac{1}{6}\).
- \(-\frac{5}{11}\cdot\frac{33}{65}=-\frac{3}{13}\).
- 2)
- \(3\frac{1}{4}\cdot3\frac{9}{13}=\frac{13}{4}\cdot\frac{48}{13}=12\).
- \(-5\frac{1}{3}\cdot1\frac{1}{2}=-\frac{16}{3}\cdot\frac{3}{2}=-8\).
- 3)
- \(\frac{5}{7}:\left(-\frac{10}{21}\right)=\frac{5}{7}\cdot\left(-\frac{21}{10}\right)=-\frac{3}{2}=-1\frac{1}{2}\).
- \(-\frac{4}{5}:\left(-1\frac{1}{15}\right)=-\frac{4}{5}:\left(-\frac{16}{15}\right)=\frac{3}{4}\).
- 4)
- \(\frac{5}{9}\cdot(-9)=-5\).
- \(-\frac{4}{5}:9=-\frac{4}{45}\).
- 5)
- \(6.5\cdot2.6=16.9\).
- \(-5.3\cdot7.7=-40.81\).
- 6)
- \(0.81:0.009=90\).
- \(0.1515:0.05=3.03\).
Ответ: 1) а) \(\frac{1}{6}\); б) \(-\frac{3}{13}\). 2) а) 12; б) −8. 3) а) \(-1\frac{1}{2}\); б) \(\frac{3}{4}\). 4) а) −5; б) \(-\frac{4}{45}\). 5) а) 16,9; б) −40,81. 6) а) 90; б) 3,03.
