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МатематикаРешебник по математике 5 класс Мерзляк ФГОС Задание 777
Задание 777
\[\boxed{\mathbf{777\ (777)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ 6\frac{4}{9} + 3\frac{5}{9} =\]
\[= (6 + 3) + \left( \frac{4}{9} + \frac{5}{9} \right) = 9 + \frac{9}{9} =\]
\[= 9 + 1 = 10\]
\[2)\ 10\frac{11}{19} + 5\frac{14}{19} =\]
\[= (10 + 5) + \left( \frac{11}{19} + \frac{14}{19} \right) =\]
\[= 15 + \frac{25}{19} = 15 + 1\frac{6}{19} = 16\frac{6}{19}\]
\[3)\ 2\frac{3}{13} + 2\frac{11}{13} =\]
\[= (2 + 2) + \left( \frac{3}{13} + \frac{11}{13} \right) =\]
\[= 4 + \frac{14}{13} = 4 + 1\frac{1}{13} = 5\frac{1}{13}\]
\[4)\ 1\frac{5}{8} + 3\frac{7}{8} =\]
\[= (1 + 3) + \left( \frac{5}{8} + \frac{7}{8} \right) = 4 + \frac{12}{8} =\]
\[= 4 + 1\frac{4}{8} = 5\frac{4}{8}\]
\[5)\ 1 - \frac{3}{11} = \frac{11}{11} - \frac{3}{11} = \frac{11 - 3}{11} =\]
\[= \frac{8}{11}\]
\[6)\ 1 - \frac{13}{40} = \frac{40}{40} - \frac{13}{40} =\]
\[= \frac{40 - 13}{40} = \frac{27}{40}\]
\[7)\ 4 - 1\frac{4}{7} = 3\frac{7}{7} - 1\frac{4}{7} =\]
\[= (3 - 1) + \left( \frac{7}{7} - \frac{4}{7} \right) = 2 + \frac{3}{7} =\]
\[= 2\frac{3}{7}\]
\[8)\ 10 - 9\frac{3}{10} = 9\frac{10}{10} - 9\frac{3}{10} =\]
\[= (9 - 9) + \left( \frac{10}{10} - \frac{3}{10} \right) =\]
\[= 0 + \frac{7}{10} = \frac{7}{10}\]
\[9)\ 5\frac{2}{7} - 2\frac{5}{7} = 4\frac{9}{7} - 2\frac{5}{7} =\]
\[= (4 - 2) + \left( \frac{9}{7} - \frac{5}{7} \right) = 2 + \frac{4}{7} =\]
\[= 2\frac{4}{7}\]
\[10)\ 14\frac{6}{20} - 8\frac{12}{20} =\]
\[= 13\frac{26}{20} - 8\frac{12}{20} =\]
\[= (13 - 8) + \left( \frac{26}{20} - \frac{12}{20} \right) =\]
\[= 5 + \frac{14}{20} = 5\frac{14}{20}\]
\[11)\ 8\frac{3}{14} - 5\frac{9}{14} = 7\frac{17}{14} - 5\frac{9}{14} =\]
\[= (7 - 5) + \left( \frac{17}{14} - \frac{9}{14} \right) =\]
\[= 2 + \frac{8}{14} = 2\frac{8}{14}\]
\[12)\ 7\frac{10}{21} - 4\frac{16}{21} = 6\frac{31}{21} - 4\frac{16}{21} =\]
\[= (6 - 4) + \left( \frac{31}{21} - \frac{16}{21} \right) =\]
\[= 2 + \frac{15}{21} = 2\frac{15}{21}\]
\[13)\ 14\frac{8}{31} - 6\frac{8}{31} =\]
\[= (14 - 6) + \left( \frac{8}{31} - \frac{8}{31} \right) =\]
\[= 8 + 0 = 8\]
\[= 19\frac{22}{22} - \left( 12\frac{30}{23} - 9\frac{15}{23} \right) =\]
\[= 20 - 3\frac{15}{23} = 19\frac{23}{23} - 3\frac{15}{23} =\]
\[= 16\frac{8}{23}\]
\[\boxed{\ \mathbf{777}.\ }\]
\[Сумма\ длин\ всех\ ребер\ куба:\]
\[5\ см \cdot 12 = 60\ см.\]
\[Площадь\ поверхности\ куба:\]
\[6 \cdot (5 \cdot 5) = 6 \cdot 25 = 150\ см^{2}.\]
