1/30+1/42+1/56+1/72

来源：学生作业帮编辑：作业帮分类：数学作业时间：2024/08/27 21:50:56

1/30+1/42+1/56+1/72
要简便运算快

计算过程为：
1/5*1/6+1/6*1/7+1/7*1/8+1/8*1/9
=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9
=1/5-1/9
=4/45
这一类的题都可以这么做

1/30+1/42+1/56+1/72+1/90 1/30+1/42+1/56+1/72 简算1/30+1/42+1/56+1/72＝? 1/30+1/42+1/56+1/72＝ 1/30+1/42+1/56+1/72简便算法 1/30+1/42+1/56+1/72 简算 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72 1/2+1/6+1/20+1/30+1/42+1/56+1/72等于几? 1/12+1/20+1/30+1/42+1/56+1/72+1/90=? 1/2+1/6+1/20+1/30+1/42+1/56+1/72等于多少? 1/6+1/12+1/20+1/30+1/42+1/56+1/72 简便计算 1/12+1/20+1/30+1/42+1/56+1/72+1/90