625加2.625加3.625加4.625加5.625.加10.625等于

问题描述:

625加2.625加3.625加4.625加5.625.加10.625等于

由0.625=5/8得
625+2.625+3.625+4.625+5.625+...+10.625
=625+(1+1+1+1+1+1+1+1+1)*(5/8)+(2+10)*9/2
=625+45/8+54=625+5.625+54=684.625
若是1.625+2.625+3.625+4.625+5.625+...+10.625
=(1+10)*10/2+10*0.625=55+6.25=61.25