Контрольная работа к урокам 3 – 16 6 8/11-4 2/11= 2 5/14+1 9/14= 5 6/7+3 4/7= 4 1/9-1 5/9=

Решим примеры:

1. $$6 \frac{8}{11} - 4 \frac{2}{11} = (6-4) + (\frac{8}{11} - \frac{2}{11}) = 2 + \frac{8-2}{11} = 2 + \frac{6}{11} = 2 \frac{6}{11}$$
2. $$2 \frac{5}{14} + 1 \frac{9}{14} = (2+1) + (\frac{5}{14} + \frac{9}{14}) = 3 + \frac{5+9}{14} = 3 + \frac{14}{14} = 3 + 1 = 4$$
3. $$5 \frac{6}{7} + 3 \frac{4}{7} = (5+3) + (\frac{6}{7} + \frac{4}{7}) = 8 + \frac{6+4}{7} = 8 + \frac{10}{7} = 8 + 1 \frac{3}{7} = 9 \frac{3}{7}$$
4. $$4 \frac{1}{9} - 1 \frac{5}{9} = (4 - 1) + (\frac{1}{9} - \frac{5}{9}) = 3 + (\frac{1-5}{9}) = 3 - \frac{4}{9} = \frac{3 \cdot 9}{9} - \frac{4}{9} = \frac{27}{9} - \frac{4}{9} = \frac{27-4}{9} = \frac{23}{9} = 2 \frac{5}{9}$$

Ответ:

1. $$6 \frac{8}{11} - 4 \frac{2}{11} = 2 \frac{6}{11}$$
2. $$2 \frac{5}{14} + 1 \frac{9}{14} = 4$$
3. $$5 \frac{6}{7} + 3 \frac{4}{7} = 9 \frac{3}{7}$$
4. $$4 \frac{1}{9} - 1 \frac{5}{9} = 2 \frac{5}{9}$$