1. Найдите значение выражения: 4 a) 11 · - 7 6: 15 б) - 8 в) 7+35-83 8 4 16 г) 0,5-25+3 4-13 д) 0,8+1,5 74-3,36

a) $$11 \cdot \frac{4}{7} = \frac{11 \cdot 4}{7} = \frac{44}{7} = 6 \frac{2}{7}$$

б) $$6 : \frac{8}{15} = 6 \cdot \frac{15}{8} = \frac{6 \cdot 15}{8} = \frac{90}{8} = 11 \frac{2}{8} = 11 \frac{1}{4}$$

в) $$7 \frac{5}{8} + 3 \frac{2}{3} - 8 \frac{3}{16} = 7 \frac{15}{24} + 3 \frac{16}{24} - 8 \frac{3}{16} = 10 \frac{31}{24} - 8 \frac{3}{16} = 10 \frac{31 \cdot 2}{24 \cdot 2} - 8 \frac{3 \cdot 3}{16 \cdot 3} = 10 \frac{62}{48} - 8 \frac{9}{48} = 2 \frac{53}{48} = 3 \frac{5}{48}$$

г) $$0,5 - \frac{4}{25} + \frac{3}{20} = \frac{1}{2} - \frac{4}{25} + \frac{3}{20} = \frac{1 \cdot 50}{2 \cdot 50} - \frac{4 \cdot 4}{25 \cdot 4} + \frac{3 \cdot 5}{20 \cdot 5} = \frac{50}{100} - \frac{16}{100} + \frac{15}{100} = \frac{50-16+15}{100} = \frac{49}{100} = 0,49$$

д) $$\frac{0,8+1,5}{4\frac{2}{7}-3,36} = \frac{2,3}{4\frac{2}{7}-3,36} = \frac{2,3}{4,2857-3,36} = \frac{2,3}{0,9257} = 2,4845$$

Ответ: а) $$6 \frac{2}{7}$$, б) $$11 \frac{1}{4}$$, в) $$3 \frac{5}{48}$$, г) 0,49, д) 2,4845