1+2+3+……+98+99
=(1+99)*99/2
=4950个
猜你喜欢
- 1What's your mother?__ __ your mother __?中国画在世界上很有名.(英语翻译)____
- 2已知抛物线y=(k^-2)x^-4kx+m的对称轴是直线x=2,最低点在直线y=-2/1x+2上,求这个抛物线的解析式
- 3The teacher then turned to the class and said
- 4两道七年级有关方程的数学应用题解答,要详细的过程与结果,今天就要,速度啊!
- 5You can have a talk with him about the interview这句话的with him放在此位置正确否?
- 6Because it rained,we couldn't play football的同义句
- 7This warranty service applies to the product only and does not cover installation workmanship.
- 8已知:在同一平面内,直线a∥c,且直线a到直线c的距离是3;直线b∥c,直线b到直线c的距离为5,则直线a到直线b的距离为_.
- 9为什么文章开头"我不由停住了脚步"独立成段,有什么好处?
- 10关于参考系,下述说法中正确的是( ) A.参考系必须选择静止不动的物体 B.参考系必须是和地面连在一起的物体 C.任何物体都可以被选做参考系 D.参考系就是被选做假想不动的物体