1、7/25×4/9+7/25×5/9
=7/25×(4/9+5/9)
=7/25×1
=7/25
2、60×(1/12+1/15+1/4)
=60×1/12+60×1/15+60×1/4
=5+4+15
=24
3、(5/12-3/8)×72
=5/12×72-3/8×72
=30-27
=3
4、6/7-5/24÷7/12
=6/7-5/24×12/7
=12/14-5/14
=7/14
=1/2
5、[3/4×(7/16-1/4)]÷9/13
=3/4×（7/16-4/16）×13/9
=1/4×3/16×13/3
=13/64
6、2/3-7/8+1/3
=(2/3+1/3)-7/8
=1-7/8
=1/8
7、5/6-(3/7-1/6)
=(5/6+1/6)-3/7
=1-3/7
=4/7
8、1-1/3-2/3
=1-(1/3+2/3)
=1-1
=0
9、1+3/5-1/10
=1+6/10-1/10
=1+1/2
=1又1/2
10、3/8-12/13+5/8
=3/8+5/8-12/13
=1-12/13
=1/13
