69 Сократи дроби: a) 125/75, 75/100, 24/360, 125/1000, 42/320; б) 75/300, 33/243, 820/41, 45/900, 105/1200

а)

• $$\frac{125}{75} = \frac{5\cdot25}{3\cdot25} = \frac{5}{3}$$
• $$\frac{75}{100} = \frac{3\cdot25}{4\cdot25} = \frac{3}{4}$$
• $$\frac{24}{360} = \frac{2\cdot12}{30\cdot12} = \frac{2}{30} = \frac{1}{15}$$
• $$\frac{125}{1000} = \frac{125}{8\cdot125} = \frac{1}{8}$$
• $$\frac{42}{320} = \frac{2\cdot21}{2\cdot160} = \frac{21}{160}$$

б)

• $$\frac{75}{300} = \frac{1\cdot75}{4\cdot75} = \frac{1}{4}$$
• $$\frac{33}{243} = \frac{3\cdot11}{3\cdot81} = \frac{11}{81}$$
• $$\frac{820}{41} = \frac{20\cdot41}{1\cdot41} = 20$$
• $$\frac{45}{900} = \frac{45}{20\cdot45} = \frac{1}{20}$$
• $$\frac{105}{1200} = \frac{5\cdot21}{5\cdot240} = \frac{21}{240} = \frac{3\cdot7}{3\cdot80} = \frac{7}{80}$$

Ответ: а) 5/3, 3/4, 1/15, 1/8, 21/160; б) 1/4, 11/81, 20, 1/20, 7/80.