五分钟完成追加30分,十分钟追加20.

1.1/2+1/3-2/3=1/6
2.1/2+1/5-2/5=3/10
3.1/2+1/7-2/7=5/14
4.1/2+1/9-2/9=7/18
5.1/2+1/11-2/11=9/22
6.1/2+1/13-2/13=11/26
7.1/2+1/15-2/15=13/30
8.1/2+1/17-2/17=15/34
9.1/2+1/19-2/19=17/38
10.1/2+1/21-2/21=19/42
11.1/2+1/23-2/23=21/46
12.1/2+1/25-2/25=23/50
13.1/2+1/27-2/27=25/54
14.1/2+1/29-2/29=27/58
1.1/2-1/4+3/4=1
2.1/2-1/6+5/6=7/6
3.1/2-1/8+7/8=5/4
4.1/2-1/10+9/10=13/10
5.1/2-1/12+11/12=4/3
6.1/2-1/24+13/24=1