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
答
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