3. Выполните действия с дробями: а) 8/21 + 3/14, 35/42 + 34/63, 7/24 + 31/40; б) 7/8 − 5/24, 29/60 − 7/30, 13/15 − 13/20; в) 4 4/5 + 1/3, 6 1/6 + 2 5/18, 17 3/7 + 5 13/14; г) 7 7/24 − 3 7/30, 8 9/16 − 4 5/12, 13 1/15 − 4 7/20, 10 5/28 − 7 37/42.

\(\frac8{21}+\frac3{14}=\frac{16}{42}+\frac9{42}=\frac{25}{42}\).

\(\frac{35}{42}+\frac{34}{63}=\frac{105}{126}+\frac{68}{126}=\frac{173}{126}=1\frac{47}{126}\).

\(\frac7{24}+\frac{31}{40}=\frac{35}{120}+\frac{93}{120}=\frac{128}{120}=1\frac1{15}\).

\(\frac78-\frac5{24}=\frac{21}{24}-\frac5{24}=\frac23\).

\(\frac{29}{60}-\frac7{30}=\frac{29}{60}-\frac{14}{60}=\frac14\).

\(\frac{13}{15}-\frac{13}{20}=\frac{52}{60}-\frac{39}{60}=\frac{13}{60}\).

\(4\frac45+\frac13=4+\frac{12}{15}+\frac5{15}=5\frac1{15}\).

\(6\frac16+2\frac5{18}=8+\frac3{18}+\frac5{18}=8\frac49\).

\(17\frac37+5\frac{13}{14}=22+\frac6{14}+\frac{13}{14}=23\frac5{14}\).

\(7\frac7{24}-3\frac7{30}=4+\frac{35}{120}-\frac{28}{120}=4\frac7{120}\).

\(8\frac9{16}-4\frac5{12}=4+\frac{27}{48}-\frac{20}{48}=4\frac7{48}\).

\(13\frac1{15}-4\frac7{20}=9+\frac4{60}-\frac{21}{60}=8\frac{43}{60}\).

\(10\frac5{28}-7\frac{37}{42}=3+\frac{15}{84}-\frac{74}{84}=2\frac{25}{84}\).