Вычислите: 1) 2/3÷(-2) (-3/4)÷1 1/2 -4/5÷8 2) 4÷(-1/2) 5÷(-5/8) (-6)÷(-3/5) 3) (-5/6)÷(-5/12) -3 3/4÷1 1/2 1 7/9÷(-2 2/3) 4) (-8 2/5)÷7 (-7 1/2)÷(-5) 4 2/3÷(-1 1/6) !

Ответ:

Olga2907

07.10.2020 07:59

1)

$\frac{2}{3} \div ( - 2) = - ( \frac{2}{3} \div \frac{2}{1} ) = - ( \frac{2}{3} \times \frac{1}{2}) = - ( \frac{2 \times 1}{3 \times 2} ) = - \frac{1}{3}$

$( - \frac{3}{4} ) \div 1 \frac{1}{2} = - ( \frac{3}{4} \div \frac{3}{2}) = - (\frac{3}{4} \times \frac{2}{3} ) = - ( \frac{3 \times 2}{4 \times 3} ) = - \frac{1}{2} = - 1.5$

$- \frac{4}{5} \div 8 = - ( \frac{4}{8} \div \frac{8}{1} ) = - ( \frac{4}{8} \times \frac{1}{8} ) = - ( \frac{4 \times 1}{8 \times 8} ) = - \frac{1}{16}$

2)

$4 \div ( - \frac{1}{2} ) = - ( \frac{4}{1} \div \frac{1}{2} ) = - ( \frac{4}{1} \times \frac{2}{1} ) = - ( \frac{4 \times 2}{1 \times 1} ) = - \frac{8}{1} = - 8$

$5 \div ( - \frac{5}{8} ) = - ( \frac{5}{1} \div \frac{5}{8} ) = - ( \frac{5}{1} \times \frac{8}{5} ) = - ( \frac{5 \times 8}{1 \times 5}) = - \frac{8}{1} = - 8$

$( - 6) \div ( - \frac{3}{5} ) = \frac{6}{1} \div \frac{3}{5} = \frac{6}{1} \times \frac{5}{3} = \frac{6 \times 5}{1 \times 3} = \frac{10}{1} = 10$

3)

$( - \frac{5}{6} ) \div ( - \frac{5}{12} ) = \frac{5}{6} \times \frac{12}{5} = \frac{5 \times 12}{6 \times 5} = \frac{2}{1} = 2$

$- 3 \frac{3}{4} \div 1 \frac{1}{2} = - ( \frac{15}{4} \div \frac{3}{2} ) = - ( \frac{15}{4} \times \frac{2}{3} ) = - ( \frac{15 \times 2}{4 \times 3}) = - \frac{5}{2} = - 2 \frac{1}{2}$

$1 \frac{7}{9} \div ( - 2 \frac{2}{3} ) = - ( \frac{16}{9} \div \frac{8}{3} ) = - ( \frac{16}{9} \times \frac{3}{8} ) = - ( \frac{16 \times 3}{9 \times 8} ) = - \frac{2}{3}$

4)

$( - 8 \frac{2}{5} ) \div 7 = - ( \frac{42}{5} \div \frac{7}{1} ) = - ( \frac{42}{5} \times \frac{1}{7}) = - ( \frac{42 \times 1}{5 \times 7} ) = - \frac{6}{5} = - 1 \frac{1}{5}$

$( - 7 \frac{1}{2} ) \div ( - 5) = \frac{15}{2} \div \frac{5}{1} = \frac{15}{2} \times \frac{1}{5} = \frac{15 \times 1}{2 \times 5} = \frac{3}{2} = 1 \frac{1}{2}$

$4 \frac{2}{3} \div ( - 1 \frac{1}{6}) = - ( \frac{14}{3} \div \frac{7}{6}) = - ( \frac{14}{3} \times \frac{6}{7} ) = - ( \frac{14 \times 6}{3 \times 7} ) = - \frac{4}{1} = - 4$