100-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20怎样简便计算

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/08 21:48:07

100-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20怎样简便计算
100-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20怎样简便计算

100-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20怎样简便计算
100-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20
=100-(1+20)*20÷2
=100-210
=-110

100-1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20
=100-(1+2+3+------+20)
=100-[(1+20)*20]/2
=100-21-
=-110

=100-(1+2+3+4+。。。。+20)
=100-(1+20)x10
=100-210
=-110

100-(1+2+3+4......)=100-(1+19+2+18.....+20)=100-(20x10+10)=-10

原式=100-【(1+20)+(2+19)+(3+18)+(4+17)+(5+16)+(6+15)+(7+14)+(8+13)+(9+12)+(10+11)】
=100-21*10
=100-210
=-110