А) 1/4+2/3 = 3/12 + 8/12 = 11/12
б)2/7+2/3 = 6/21 + 14/21 = 20/21
в)2/5+1/4 = 8/20 + 5/20 = 13/20
г)1\2+ 1/3 = 3/6 + 2/6 = 5/6
д)1/3+3/5 = 5/15 + 9/15 = 14/15
е)4/5+1/2 = 8/10 + 5/10 = 13/10 = 1 3/10 = 1,3
д)1/3+3/5 = 5/15 + 9/15 = 14/15
е)4/5+1/2 = 8/10 + 5/10 = 13/10 = 1 3/10 = 1,3
ж)1/2+5/7 = 7/14 + 10/14 = 17/14 = 1 3/14
з)2/3 +3/10