简算1/7+3/5+2/5+5/7 3/4+6/13+7/13-1/4

问题描述:

简算1/7+3/5+2/5+5/7 3/4+6/13+7/13-1/4
简算1/7+3/5+2/5+5/7 3/4+6/13+7/13-1/4

1/7+3/5+2/5+5/7
=1/7+5/7+3/5+2/5
=6/7+1
=1又6/7
3/4+6/13+7/13-1/4
=3/4-1/4+6/13+7/13
=1/2+1
=1又1/2