1/12+1/20+1/30+1/42+1/56+1/72+1/90=?

来源：学生作业帮编辑：大师作文网作业帮分类：数学作业时间：2024/11/11 13:13:28

1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1/3-1/10
=7/30
（将1/4~1/9消去)
给分啊~!

1/12+1/20+1/30+1/42+1/56+1/72+1/90=? 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90= 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=多少 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=______ 1/12+1/20+1/30+1/42+1/56+1/72+1/90 1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=? 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+.1/9900 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/10 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110 谁能巧算1-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90 若a=1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110+1/132+1/ 1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110 急!