Выполним вычисления:
1) $$\frac{3}{8} \cdot 48 = \frac{3 \cdot 48}{8} = \frac{3 \cdot 6 \cdot 8}{8} = 3 \cdot 6 = 18$$
2) $$0{,}5 \cdot 28 = \frac{1}{2} \cdot 28 = \frac{28}{2} = 14$$
3) $$\frac{5}{14} \cdot 70 = \frac{5 \cdot 70}{14} = \frac{5 \cdot 5 \cdot 14}{14} = 5 \cdot 5 = 25$$
4) $$\frac{1}{7} \cdot 3{,}5 = \frac{1}{7} \cdot \frac{35}{10} = \frac{1 \cdot 5 \cdot 7}{7 \cdot 2 \cdot 5} = \frac{1}{2} = 0{,}5$$
5) $$\frac{9}{16} \cdot 32 = \frac{9 \cdot 32}{16} = \frac{9 \cdot 2 \cdot 16}{16} = 9 \cdot 2 = 18$$
6) $$\frac{5}{18} \cdot 90 = \frac{5 \cdot 90}{18} = \frac{5 \cdot 5 \cdot 18}{18} = 5 \cdot 5 = 25$$
7) $$1 \frac{1}{4} \cdot \frac{4}{5} = \frac{5}{4} \cdot \frac{4}{5} = 1$$
8) $$0{,}2 \cdot \frac{1}{2} = \frac{2}{10} \cdot \frac{1}{2} = \frac{2}{20} = \frac{1}{10} = 0{,}1$$
9) $$\frac{11}{15} \cdot 15 = 11$$
10) $$\frac{5}{6} \cdot 30 = \frac{5 \cdot 30}{6} = \frac{5 \cdot 5 \cdot 6}{6} = 5 \cdot 5 = 25$$
11) $$\frac{3}{11} \cdot 3{,}3 = \frac{3}{11} \cdot \frac{33}{10} = \frac{3 \cdot 3 \cdot 11}{11 \cdot 10} = \frac{9}{10} = 0{,}9$$
12) $$0{,}01 \cdot \frac{1}{3} = \frac{1}{100} \cdot \frac{1}{3} = \frac{1}{300}$$
13) $$\frac{3}{5} \cdot 30 = \frac{3 \cdot 30}{5} = \frac{3 \cdot 6 \cdot 5}{5} = 3 \cdot 6 = 18$$
14) $$\frac{1}{9} \cdot 18 = \frac{18}{9} = 2$$
15) $$\frac{4}{17} \cdot 17 = 4$$