Сократите: 1) 6*14/7*30 2) 22*10/15*33 3) 9*2*3/8*18*21 4) 8*7+8*3/16*25-16*5

1. $\frac{6 \times 14}{7 \times 30} = \frac{84}{210}$, сокращаем на 42: $\frac{84 \div 42}{210 \div 42} = \frac{2}{5}$.

2. $\frac{22 \times 10}{15 \times 33} = \frac{220}{495}$, сокращаем на 5: $\frac{220 \div 5}{495 \div 5} = \frac{44}{99}$, затем сокращаем на 11: $\frac{44 \div 11}{99 \div 11} = \frac{4}{9}$.

3. $\frac{9 \times 2 \times 3}{8 \times 18 \times 21} = \frac{54}{3024}$, сокращаем на 54: $\frac{54 \div 54}{3024 \div 54} = \frac{1}{56}$.

4. $8 \times 7 + \frac{8 \times 3}{16 \times 25} - 16 \times 5 = 56 + \frac{24}{400} - 80$. Упрощаем дробь $\frac{24}{400} = \frac{3}{50}$. Теперь вычисляем: $56 + \frac{3}{50} - 80 = -24 + \frac{3}{50} = -\frac{1200}{50} + \frac{3}{50} = \frac{-1200 + 3}{50} = \frac{-1197}{50}$.

Ответы:

1. $\frac{2}{5}$

2. $\frac{4}{9}$

3. $\frac{1}{56}$

4. $\frac{-1197}{50}$