разрядным слагаемым: 81 903; в) 9000; г) 136 000 200. 3) 18 + 4/19; д) 2 7/9 + 8/9; ж) 4 1/2 + 3 1/4; г) 23 + 9/10; e) 15 8/11 + 4 3/11; 3) 5 1/7 + 3 20/21; в) 6 - 2/5; д) 4 1/7 - 1 4/7; ж) 4 1/2 - 3 1/4; 3) 5 1/7 - 3 20/21,

Ответ:

в) 18 + 4/19;

\[18 + \frac{4}{19} = \frac{18 \cdot 19 + 4}{19} = \frac{342 + 4}{19} = \frac{346}{19} = 18\frac{4}{19}\]

г) 23 + 9/10;

\[23 + \frac{9}{10} = \frac{23 \cdot 10 + 9}{10} = \frac{230 + 9}{10} = \frac{239}{10} = 23\frac{9}{10}\]

д) 2 7/9 + 8/9;

\[2\frac{7}{9} + \frac{8}{9} = \frac{2 \cdot 9 + 7}{9} + \frac{8}{9} = \frac{18 + 7}{9} + \frac{8}{9} = \frac{25}{9} + \frac{8}{9} = \frac{33}{9} = \frac{11}{3} = 3\frac{2}{3}\]

e) 15 8/11 + 4 3/11;

\[15\frac{8}{11} + 4\frac{3}{11} = \frac{15 \cdot 11 + 8}{11} + \frac{4 \cdot 11 + 3}{11} = \frac{165 + 8}{11} + \frac{44 + 3}{11} = \frac{173}{11} + \frac{47}{11} = \frac{220}{11} = 20\]

3) 5 1/7 + 3 20/21;

\[5\frac{1}{7} + 3\frac{20}{21} = \frac{5 \cdot 7 + 1}{7} + \frac{3 \cdot 21 + 20}{21} = \frac{35 + 1}{7} + \frac{63 + 20}{21} = \frac{36}{7} + \frac{83}{21} = \frac{36 \cdot 3}{7 \cdot 3} + \frac{83}{21} = \frac{108}{21} + \frac{83}{21} = \frac{191}{21} = 9\frac{2}{21}\]

в) 6 - 2/5;

\[6 - \frac{2}{5} = \frac{6 \cdot 5 - 2}{5} = \frac{30 - 2}{5} = \frac{28}{5} = 5\frac{3}{5}\]

д) 4 1/7 - 1 4/7;

\[4\frac{1}{7} - 1\frac{4}{7} = \frac{4 \cdot 7 + 1}{7} - \frac{1 \cdot 7 + 4}{7} = \frac{28 + 1}{7} - \frac{7 + 4}{7} = \frac{29}{7} - \frac{11}{7} = \frac{18}{7} = 2\frac{4}{7}\]

ж) 4 1/2 - 3 1/4;

\[4\frac{1}{2} - 3\frac{1}{4} = \frac{4 \cdot 2 + 1}{2} - \frac{3 \cdot 4 + 1}{4} = \frac{8 + 1}{2} - \frac{12 + 1}{4} = \frac{9}{2} - \frac{13}{4} = \frac{9 \cdot 2}{2 \cdot 2} - \frac{13}{4} = \frac{18}{4} - \frac{13}{4} = \frac{5}{4} = 1\frac{1}{4}\]

3) 5 1/7 - 3 20/21

\[5\frac{1}{7} - 3\frac{20}{21} = \frac{5 \cdot 7 + 1}{7} - \frac{3 \cdot 21 + 20}{21} = \frac{35 + 1}{7} - \frac{63 + 20}{21} = \frac{36}{7} - \frac{83}{21} = \frac{36 \cdot 3}{7 \cdot 3} - \frac{83}{21} = \frac{108}{21} - \frac{83}{21} = \frac{25}{21} = 1\frac{4}{21}\]

Ответ: