简便计算1988-1985+1982-1979+······+8-5+2=
问题描述:
简便计算1988-1985+1982-1979+······+8-5+2=
答
1988-1985+1982-1979+······+8-5+2
= (1988-1985)+(1982-1979)+······+(8-5)+2
= 3+3+. + 3 + 2
= 3x661 + 2
= 1983+2
= 1985后来我想通了,你这有问题,662还要/2,662是有几个数字,我们要算的是有几组(大数减小数),是331*3+2+995噢,你说的对
我搞错了
最总共有331个3
1988= 2+6x331
1982 = 2+6x330
1976 = 2+6x329
... ...
22 = 2+6x3
14 = 2+6x2
8 = 2+6x1