Пошаговое объяснение:
1) 4/7+2/5 = 4(5)/7+2(7)/5 = 20+14/35 = 34/35
2) 7/12-5/9 = 7(3)/12-5(4)/9 = 21-20/36 = 1/36
3) 2 3/4+3 2/5 = 11/4+17/5 = 11(5)/4+17(4)/5 = 55+67/20 = 6 1/10
4) 3 4/9-2 1/6 = 31/9-13/6 = 31(2)/9-13(3)/6 = 62-39/18 = 1 5/18
Пошаговое объяснение:
1) 4/7+2/5 = 4(5)/7+2(7)/5 = 20+14/35 = 34/35
2) 7/12-5/9 = 7(3)/12-5(4)/9 = 21-20/36 = 1/36
3) 2 3/4+3 2/5 = 11/4+17/5 = 11(5)/4+17(4)/5 = 55+67/20 = 6 1/10
4) 3 4/9-2 1/6 = 31/9-13/6 = 31(2)/9-13(3)/6 = 62-39/18 = 1 5/18