3. Выполните действие и сократите результат: 1) 7/15 + 2/15; 2) 37/46 - 21/46; 3) 5/36 + 17/36; 4) 17/63 - 9/63.

Выполним действия с дробями:

1. \( \frac{7}{15} + \frac{2}{15} = \frac{7+2}{15} = \frac{9}{15} = \frac{9 \div 3}{15 \div 3} = \frac{3}{5} \)

2. \( \frac{37}{46} - \frac{21}{46} = \frac{37-21}{46} = \frac{16}{46} = \frac{16 \div 2}{46 \div 2} = \frac{8}{23} \)

3. \( \frac{5}{36} + \frac{17}{36} = \frac{5+17}{36} = \frac{22}{36} = \frac{22 \div 2}{36 \div 2} = \frac{11}{18} \)

4. \( \frac{17}{63} - \frac{9}{63} = \frac{17-9}{63} = \frac{8}{63} \)