А)7-4_5/9б)4_3/10+1_5/12в)6_13/21+2_9/14г)5_1/6-3_3/4а)7-4_5/9 б)4_3/10+1_5/12 в)6_13/21+2_9/14 г)5_1/6-3_3/4

А)7-4_5/9=7/1-41/9=(63-41)/9=22/9=2 4/9
б)4_3/10+1_5/12=43/10+17/12=(258+85)/60=343/60=5 43/60
в)6_13/21+2_9/14=139/21+37/14=(278+111)/42=389/42=9 11/42
Г)5_1/6-3_3/4=31/6-15/4=(62-45)/12=17/12