Контрольная работа «Смешанные числа» Вариант 2 1. Найдите: 1) 8 - 2 + ; 2) 6 - 2 ; 3) 7 - 4 ; 4) 25 + 76 ; 5) 17 - 5 5 9

1. Найдите:

1) $$8 \frac{16}{23} - 2 \frac{3}{23} + \frac{12}{23} = (8 - 2) + (\frac{16}{23} - \frac{3}{23} + \frac{12}{23}) = 6 + \frac{16 - 3 + 12}{23} = 6 + \frac{25}{23} = 6 + \frac{23 + 2}{23} = 6 + 1 \frac{2}{23} = 7 \frac{2}{23}$$

2) $$6 \frac{5}{11} - 2 \frac{6}{11} = (6 - 2) + (\frac{5}{11} - \frac{6}{11}) = 4 + (\frac{5 - 6}{11}) = 4 - \frac{1}{11} = 3 + 1 - \frac{1}{11} = 3 + \frac{11}{11} - \frac{1}{11} = 3 + \frac{11-1}{11} = 3 + \frac{10}{11} = 3 \frac{10}{11}$$

3) $$7 - 4 \frac{4}{5} = (7 - 4) - \frac{4}{5} = 3 - \frac{4}{5} = 2 + 1 - \frac{4}{5} = 2 + \frac{5}{5} - \frac{4}{5} = 2 + \frac{5-4}{5} = 2 + \frac{1}{5} = 2 \frac{1}{5}$$

4) $$25 \frac{2}{9} + 76 \frac{8}{9} = (25 + 76) + (\frac{2}{9} + \frac{8}{9}) = 101 + \frac{2 + 8}{9} = 101 + \frac{10}{9} = 101 + 1 \frac{1}{9} = 102 \frac{1}{9}$$

5) $$17 \frac{1}{2} - 5 = (17 - 5) + \frac{1}{2} = 12 + \frac{1}{2} = 12 \frac{1}{2}$$

Ответ: 1) $$7 \frac{2}{23}$$, 2) $$3 \frac{10}{11}$$, 3) $$2 \frac{1}{5}$$, 4) $$102 \frac{1}{9}$$, 5) $$12 \frac{1}{2}$$