简便运算分数题(有分!)
发布网友
发布时间：2024-10-18 05:18
共1个回答
热心网友
时间：2024-11-30 08:26
1.
1-5/6+7/12-9/20+11/30-13/42+15/56-17/72
=1-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)-(1/8+1/9)
=1-1/2-1/9
=7/18
2.
1/3+3/4+2/5+5/7+7/8+9/20+10/21+11/24+19/35
=1/3+3/4+2/5+5/7+7/8+(1/4+1/5)+(1/3+1/7)+(1/3+1/8)+(2/5+1/7)
=3*(1/3)+(3/4+1/4)+(2/5+1/5+2/5)+(5/7+1/7+1/7)+(7/8+1/8)
=1+1+1+1+1
=5
3.
1/2+5/6-7/12+9/20-1/30+13/42-15/56+17/72
=1-1/2+(1/2+1/3)-(1/3+1/4)+(1/4-1/5)-(1/5-1/6)+(1/6+1/7)-(1/7+1/8)+(1/8+1/9)
=1+1/9
=10/9
4.
1/2+1/6+1/12+1/20+1/30+1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7
