69. Вычислите: 1) 1/4 + 3/5; 2) 9/11 − 2/5; 3) 13/16 − 9/32; 4) 3/28 + 5/14; 5) 14/15 − 7/10; 6) 3/8 + 1/6; 7) 9/25 − 7/20; 8) 37/42 − 17/24; 9) 11/24 − 3/16; 10) 9/16 + 7/24 − 3/8; 11) 1/3 − 1/6 + 1/4; 12) 2/5 + 4/15 − 5/9.

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Accepted Answer

\(\frac14+\frac35=\frac5{20}+\frac{12}{20}=\frac{17}{20}\).
\(\frac9{11}-\frac25=\frac{45}{55}-\frac{22}{55}=\frac{23}{55}\).
\(\frac{13}{16}-\frac9{32}=\frac{26}{32}-\frac9{32}=\frac{17}{32}\).
\(\frac3{28}+\frac5{14}=\frac3{28}+\frac{10}{28}=\frac{13}{28}\).
\(\frac{14}{15}-\frac7{10}=\frac{28}{30}-\frac{21}{30}=\frac7{30}\).
\(\frac38+\frac16=\frac9{24}+\frac4{24}=\frac{13}{24}\).
\(\frac9{25}-\frac7{20}=\frac{36}{100}-\frac{35}{100}=\frac1{100}\).
\(\frac{37}{42}-\frac{17}{24}=\frac{148}{168}-\frac{119}{168}=\frac{29}{168}\).
\(\frac{11}{24}-\frac3{16}=\frac{22}{48}-\frac9{48}=\frac{13}{48}\).
\(\frac9{16}+\frac7{24}-\frac38=\frac{27}{48}+\frac{14}{48}-\frac{18}{48}=\frac{23}{48}\).
\(\frac13-\frac16+\frac14=\frac4{12}-\frac2{12}+\frac3{12}=\frac5{12}\).
\(\frac25+\frac4{15}-\frac59=\frac{18}{45}+\frac{12}{45}-\frac{25}{45}=\frac5{45}=\frac19\).

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