计算1/2+5/7+(-1/2)+2/7 1/2读作2分之1

问题描述:

计算1/2+5/7+(-1/2)+2/7 1/2读作2分之1

1/2+5/7+(-1/2)+2/7
=1/2+5/7-1/2+2/7
=(1/2-1/2)+(5/7+2/7)
=0+1
=1