简便运算,越简便越好9+19+29+39+49+59+69+79+89+99
来源:学生作业帮助网 编辑:作业帮 时间:2024/11/17 04:47:20
xO1n@0D5>Jg?)< nN*R*@(tBn
IAt:jvgl4bܯG%Ft@f/?oY"{,K\}O(T>@V}XgNx`}of ]lEjL -B@06C B`
15̢WK3E얘0uљG⢹[
W|*
简便运算,越简便越好9+19+29+39+49+59+69+79+89+99
简便运算,越简便越好9+19+29+39+49+59+69+79+89+99
简便运算,越简便越好9+19+29+39+49+59+69+79+89+99
你可以发现9+99=19+89=……=49+59=108
所以原式=9+19+29+39+49+59+69+79+89+99
=108×5
=540
(10+20+30+40+50+60+70+80+90+100)-10
10*10-10
=10+20+30+40+50+60+70+80+90+100-10
=110*5-10
=540
10^55-10=540
9+19+29+39+49+59+69+79+89+99
=9*10+90*(10/2)=540