a) 4/9 + 4/9 = 2(4/9) = 8/9.

б) 11/13 + 2/13 = (11+2)/13 = 13/13 = 1

в) 24/30 - 14/30 = (24-14)/30 = 10/30 = 1/3

г) 15/19 - 9/19 = (15-9)/19 = 6/19

д) 14/15 - (7/15 + 3/15) = (14-(7+3))/15 = 4/15.

е) 20/32 - (7/32 - 3/32) = (20-(7-3))/32 = 16/32 = 1/2

2. а) х - 5/18 = 8/18

х = 8/18 + 5/18

х = (8+5)/18

х = 13/18

б) 3/15 + (4/15 - х) = 4/15

4/15 - х = 4/15 - 3/15

х = 4/15 - 1/15

х = 3/15