简便计算:2.5-5/12-1/6+2/7

问题描述:

简便计算:2.5-5/12-1/6+2/7

2.5-5/12-1/6+2/7
=2.5+2/7-(5/12+1/6)
=2又11/14-7/12
=2又17/84