1/2-(0.875*2/13+1/6.5/8)*1又6/7

问题描述:

1/2-(0.875*2/13+1/6.5/8)*1又6/7

1/2-(0.875*2/13+1/6.5/8)*1又6/7
=1/2-[(7/8)*(2/13)+(2/13)*(1/8)]*(13/7)
=1/2-[(2/13)*(7/8+1/8)]*(13/7)
=1/2-(2/13)*(13/7)
=1/2-2/7
=7/14-4/14
=3/14