(101+103+......+199)-(90+92+......+188)等于多少???

每一个括号里都是50个数
对应相减都等于11，即101-90=11
103-92=11
.........
199-188=11
所以结果是50*11=550

(101+103+......+199)-(90+92+......+188)
=(101+199)*50/2 - (90+188)*50/2
=(300)*50/2 - (278)*50/2
=25*(300-278)
=550

(101+103+......+199)-(90+92+......+188)
=11+11+......+11(共50个11)
=550

101 - 90 = 11
103-92 = 11
.....
199-188 = 11

结果 11 * 50 = 550

(101+103+......+199)-(90+92+......+188)
=101-90+103-92+......+199-188
=11+11+......+11
=11*50
=550

=11×99
=1100-11=1089