По действиям:
(3+1/ 5/12+1/3)= 3+ 1/ 5/12+4/12 = 3+ 1/ 9/12= 3+(1:9/12)= 3+ (12/12* 12/9)= 3+ 1 1/3= 4 1/3
2+ 1/ 3+3/4 = 2+ 1/ 2 4/4+3/4 = 2+ 1/ 2 7/4= 2+ 1/ 15/4= 2+ (1:15/4)= 2+ (4/4*4/15)= 2 4/15
1+1/ 1+2/3= 1+ 1/ 3/3+2/3= 1+ 1/ 5/3= 1+ (1:5/3)= 1+ (3/3*3/5)= 1 3/5
4 1/3 + 2 4/15 + 1 3/5=
13/3 + 34/15 + 8/5=
65/15 + 34/15 + 24/15=
123/15= 8 1/5