1+2+3+4+5+6+7+8+9+10+12+13+14+……………………………………………………+9997+9998+9999+10000=?

问题描述:

1+2+3+4+5+6+7+8+9+10+12+13+14+……………………………………………………+9997+9998+9999+10000=?

(1+10000)×10000/2=5000×10001=50005000