jacky
问题补充说明：都是分数加减的。
列如：
2/3-7/8+1/3
=(2/3+1/3)-7/8
=1-7/8
=1/8
5/6-(3/7-1/6)
=(5/6+1/6)-3/7
=1-3/7
=4/7
1-1/3既呼运-2/3
=1-(1/3+2/3)
=1-1
=0
1+3/5-1/10
=1+6/10-1/10
=1+1/2
=1又1/2
3/8-12/13+5/8
=3/8+5/8-12/13
=1-12/13
=1/13
1-(1/2-3/4旧维或)
=1+3/4-2/4
=1+1/4
=5/4
1-1/2-1/4
=1/2-1/4
=2/4-1特测密/4
=1/4
2/7-8观观答服/9+5/7
=(2/7+5/7)-8/9
=1-8/9
=1/9
2-1/4-3/4
=属滑升从应钱字盾跳代友2-(1/4+3/4)
=2-1
=1
1/2-(3/8-1/2)
=1/2+1/2-3/4
=1-3/8
=5/8
