1、4/7-(1/9+1/8)
=4/7-17/72
=169/504
2、1/4+1/6-2/15
=5/12-2/15
=17/60
3、3/14+5/7+1/21
=9/42+30/42+2/42
=41/42
4、5/14-(3/10-1/5)
=5/14-1/10
=9/35
5、12又1/6-(4.6+3又2/3)
=12又1/6-3又2/3-4.6
= 8.5-4.6
=3.9
6、5+0.75-1又3/6
=5.75-1.5
=4.25
1、4/7-(1/9+1/8)
=4/7-17/72
=169/504
2、1/4+1/6-2/15
=5/12-2/15
=17/60
3、3/14+5/7+1/21
=9/42+30/42+2/42
=41/42
4、5/14-(3/10-1/5)
=5/14-1/10
=9/35
5、12又1/6-(4.6+3又2/3)
=12又1/6-3又2/3-4.6
= 8.5-4.6
=3.9
6、5+0.75-1又3/6
=5.75-1.5
=4.25