Question

1加二分之一减六分之五加十二分之一减二十分之九加三十分之十一减四十二分之十三

最好简便

Answer 1

解：1+1/2-5/6+1/12-9/20+11/30-13/42(过程可以简化一点，但这样做简单一些，虽然过程烦锁)
=3/2-5/6+1/12-9/20+11/30-13/42
=9/6-5/6+1/12-9/20+11/30-13/42
=4/6+1/12-9/20+11/30-13/42
=8/12+1/12-9/20+11/30-13/42
=9/12-9/20+11/30-13/42
=3/4-9/20+11/30-13/42
=15/20-9/20+11/30-13/42
=6/20+11/30-13/42
=3/10+11/30-13/42
=9/30+11/30-13/42
=20/30-13/42
=2/3-13/42
=28/42-13/42
=15/42
=5/14

Answer 2

1+1/2-5/6+1/12-9/20+11/30-13/42=1+(6-10+12)/12+(22-27)/60-13/42=1-5/12-1/12+13/42=1-1/2+13/42=1/2+13/42=34/42=17/21.

Answer 3

1+1/2-5/6+1/12-9/20+11/30-13/42
=1+1/2-(1/2+1/3)+(1/3-1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)
=1-1/4-1/4-1/7
=5/14