Question

奥数199+298+397+496+595+694+793+892+991等于多少,怎样解答

Answer 1

祝你学习进步 生活愉快 不懂可追问，有帮助请采纳，谢谢！

Answer 2

=(1+9)*9/2*（100+1)+90*9
=4545+810
=5355

199+298+397+496+595+694+793+892+991
=191+292+393+494+595+696+797+898+999
=101+90+202+90+303+90+404+90+505+90+606+90+707+90+808+90+909+90
然后出来上面的公式

Answer 3

=100+200+300+400+500+600+700+800+900+99+98+97+96+95+94+93+92+91
=4500+855
=5355

Answer 4

199+298+397+496+595+694+793+892+991

=(200-1)+(300-2)+(400-3)+(500-4)+(600-5)+(700-6)+(800-7)+(900-8)+(1000-1)
=(200+300+...+1000)-(1+2+...+9)
=1200*9/2-(1+9)*9/2
=5400-45
=5355

Answer 5

199+298+397+496+595+694+793+892+991

=200-1+300-2+400-3+500-4+600-5+700-6+800-7+900-8+1000-9
=（2+3+。。。。+10）×100-(1+2+....+9)
=5400-45=5355