6+7+8+9······+30等于多少?
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/06 15:56:41
![6+7+8+9······+30等于多少?](/uploads/image/z/353769-33-9.jpg?t=6%2B7%2B8%2B9%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%2B30%E7%AD%89%E4%BA%8E%E5%A4%9A%E5%B0%91%3F)
xMJ@ǯ2I& $@P^EۅB")~U2i]yAb{^&F2{sVQ|w}_EGV9'M;6L;
vñ9NZɦU*|A
D i@PV`3X]6`Ch*FگtR
auQfIu=?⩨njXN{ՠ]NGS,#ldq6v<|e~+m!Dϻ*
6+7+8+9······+30等于多少?
6+7+8+9······+30等于多少?
6+7+8+9······+30等于多少?
(6+30)*(30-6+1)/2=450
6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30
6+30=36 7+29=36总共有25个数字就是有12对加起来=36的数在加上最中间的数18
36×12+18=450
自己做到!
450
Sn= 6+7+8+...+30
=
= 450