Question

даю 10баллов решите 3 задание

Answer 1

▪ 1)
$7.8 \times \frac{4}{13} - 61.5 \div 13 \frac{2}{3} + 198.8 = 2.4 - 4.5 + 198.8 = - 2.1 + 198.8 = 196.7\\ \\ 1)7.8 \times \frac{4}{13} = \frac{78 \times 4}{10 \times 13} = \frac{6 \times 2}{5} = \frac{12}{5} = 2 \frac{2}{5} = 2.4 \\ 2) \: 61.5 \div 13 \frac{2}{3} = \frac{615}{10} \div \frac{41}{3} = \frac{123 \times 3}{2 \times 41} = \frac{3 \times 3}{2} = \frac{9}{2} = 4.5 \\ 3) \: 2.4 - 4.5 = - 2.1 \\ 4) \: - 2.1 + 198.8 = 196.7$

▪2)
$19.25 \times \frac{5}{11} + 5.76 \times \frac{5}{12} - 13.009 = \frac{1925 \times 5}{100 \times 11} + \frac{576 \times 5}{100 \times 12} - 13.009 = \frac{7 \times 5}{4 } + \frac{12}{5} - 13.009 = \frac{35}{4} + 2 \frac{2}{5} - 13.009 = 8 \frac{3}{4} + 2.4 - 13.009 = 8.75 + 2.4 - 13.009 = 11.15 - 13.009 = - 1.859$
▪3)
$4.625 \times 2 \frac{2}{15} \div 2.96 - 2 \frac{4}{7} = 4\frac{625}{1000} \times \frac{32}{15} \div 2 \frac{96}{100} - 2 \frac{4}{7} = 4 \frac{5}{8} \times \frac{32}{15} \div 2 \frac{24}{25} - 2 \frac{4}{7} = \frac{37 \times 32}{8 \times 15} \div \frac{74}{25} - 2 \frac{4}{7} = \frac{37 \times 4 \times 25}{15 \times 74} - 2 \frac{4}{7} = \frac{2 \times 5}{3 } - 2 \frac{4}{7} = 3 \frac{1}{3} - 2 \frac{4}{7} = 1 \frac{7 - 12}{21} = 1 - \frac{5}{21} = \frac{16}{21}$
▪4)
$30.25 \div 4 \frac{5}{7} \div 1.05 - 2 \frac{1}{6} = 30 \frac{1}{4} \div \frac{33}{7} \div 1 \frac{1}{20} - 2 \frac{1}{6} = \frac{121 \times 7 \times 20}{4 \times 33 \times 21} - 2 \frac{1}{6} = \frac{11 \times 5}{3 \times 3} - 2 \frac{1}{6} = 6 \frac{1}{9} - 2 \frac{1}{6} = 4 \frac{2 - 3}{18} = 4 - \frac{1}{18} = 3 \frac{17}{18}$