2. Выполни действия: 50 + 2 = 9윽-= 음+음= 42 25 4륨 + 11 = 620-220 = 10+20= 18 18

2. Выполним действия:

$$5\frac{3}{9} + 2 = (5 + 2) + \frac{3}{9} = 7 + \frac{3}{9} = 7\frac{3}{9} = 7\frac{1}{3}$$

$$9\frac{6}{7} - \frac{2}{7} = 9\frac{6-2}{7} = 9\frac{4}{7}$$

$$\frac{9}{12} + \frac{8}{12} = \frac{9 + 8}{12} = \frac{17}{12} = 1\frac{5}{12}$$

$$4\frac{4}{15} + 2\frac{3}{5} = 4\frac{4}{15} + 2\frac{3 \cdot 3}{5 \cdot 3} = 4\frac{4}{15} + 2\frac{9}{15} = (4+2) + (\frac{4}{15} + \frac{9}{15}) = 6 + \frac{4+9}{15} = 6 + \frac{13}{15} = 6\frac{13}{15}$$

$$4\frac{2}{18} + 1\frac{1}{18} = (4 + 1) + (\frac{2}{18} + \frac{1}{18}) = 5 + \frac{2+1}{18} = 5 + \frac{3}{18} = 5\frac{3}{18} = 5\frac{1}{6}$$

$$6\frac{8}{20} - 2\frac{5}{20} = (6 - 2) + (\frac{8}{20} - \frac{5}{20}) = 4 + \frac{8 - 5}{20} = 4 + \frac{3}{20} = 4\frac{3}{20}$$

$$\frac{8}{20} + \frac{5}{20} = \frac{8 + 5}{20} = \frac{13}{20}$$

Ответ: $$5\frac{3}{9} + 2 = 7\frac{1}{3}$$, $$9\frac{6}{7} - \frac{2}{7} = 9\frac{4}{7}$$, $$\frac{9}{12} + \frac{8}{12} = 1\frac{5}{12}$$, $$4\frac{4}{15} + 2\frac{3}{5} = 6\frac{13}{15}$$, $$4\frac{2}{18} + 1\frac{1}{18} = 5\frac{1}{6}$$, $$6\frac{8}{20} - 2\frac{5}{20} = 4\frac{3}{20}$$, $$\frac{8}{20} + \frac{5}{20} = \frac{13}{20}$$