Ответ: 1) 7/10 +3 /5 =  7/10 + 3*2/10 = 7/10 + 6/10 =13/102) 1/6 + 2/3 = 1/6 + 2*2/6=1/6+4/6 = 5/63)13/10 -5/6 = 13*3/30 — 5*5/30 = 39/30 — 25/30 = 14/30 = 7/15