1+2-3+4+5-6+7+8-9+10+…+28+29-30,
=(1+2-3)+(4+5-6)+(7+8-9)+…+(28+29-30),
=0+3+6+9+…+27,
=(0+27)×10÷2,
=135.
故答案为:135
1+2-3+4+5-6+7+8-9+10+…+28+29-30=_.
1+2-3+4+5-6+7+8-9+10+…+28+29-30=______.
数学人气:159 ℃时间:2020-03-21 16:36:19
优质解答
我来回答
类似推荐
猜你喜欢
- 1世界历史上最短的信除了雨果那封还有吗
- 2last sunday I went to the children's palace .It was very big and beautiful.first,I saw the big hall
- 3mike my that is uncle 连词成句
- 4已知(2x-y-3)的平方+x-2y的绝对值=0,则Xy各为多少?
- 51.若4x-3y=0,且x=0,y≠0,求4x+5y分之4x-5y
- 6he said i was hard-working 为什么这句话中有两个过去式?
- 7为了证明地球是个球体,小明收集了以下证据:①远离海岸的帆船,船身比桅杆先消失;②日食时,日轮的缺损部分为圆弧形;③远处的事物无法看清;④月食时,月轮缺损的部分为圆弧形.
- 8形容年纪很大.的四字词语如七?
- 980÷40%X=½ X等于多少?
- 10what do you usually do on sundays用next sunday代替on sundays