Question

решить и напишите решение полностью

Answer 1

Объяснение:

$1) \frac{3}{7} \div \frac{4}{5 } = \frac{3 \times 5}{7 \times 4} = \frac{15}{28}$

$2)(1.2 \div \frac{9}{20} - 2 \frac{3}{8} ) \div 0.7 = ( \frac{6 \times 20}{5 \times 9} - 2 \frac{3}{8} ) \div \frac{7}{10} = ( \frac{8}{3} - 2 \frac{3}{8} ) \div \frac{7}{10} = (2 \frac{16}{24} - 2 \frac{9}{24} ) \div \frac{7}{10} = = \frac{7}{24} \div \frac{7}{10} = \frac{10}{24} = \frac{5}{12}$

$3) \frac{2}{5} - 1 \frac{3}{4} = \frac{2}{5} - \frac{7}{4} = \frac{8 - 35}{20} = - \frac{27}{20} = - 1 \frac{7}{20}$

$4)( - \frac{5}{18} ) + ( - 0.18) = - \frac{5}{18} - \frac{9}{50} = - \frac{125 + 81}{450} = - \frac{206}{450} = - \frac{103}{225}$

$5)( - 7) \times 14 = - 98$

$6)800km \: per \: hour \: = 100\% \\ 800 \div 100 = 8(1\%) \\ 8 \times 70 = 560(70\%) \\ 800 - 560 = 240km \: per \: hour$