来自李彦平的问题
12+56+1112+1920+…+379380=______.
12+56+1112+1920+…+379380=______.
1回答
2020-05-22 22:27
12+56+1112+1920+…+379380=______.
12+56+1112+1920+…+379380=______.
12+56+1112+1920+…+379380,=(1-12)+(1-16)+(1-112)+(1-120)+…+(1-1380),=19-(12+16+112+120+…+1380),=19-(1-12+12-13+13-14+…+119-120),=19-1+120,=18120.故答案为:18120....