3/5+3/4-5/6 8/9+2/7+5/7 15/8-3/4-1/4
=36/60+45/60-50/60 =8/9+1 =15/8-1
=31/60 =17/9 =7/8
9/7-1/6+3/7 7/4-12/23-3/4 5-6(3/8+1/6)
= 12/7-1/6 = 1-12/23 =5-(9/4+1)
= 72/42-7/42 =11/23 =7/4
=65/42