Question

123+234+345+456+567+678+789=

不能做加法

Answer 1

123+234+345+456+567+678+789
=123*7+111*(1+2+3+4+5+6)=123*7+111*21=3192
或
123+234+345+456+567+678+789
==(100+700)*(7/2)+(20+80)*(7/2)+(3+9)*(7/2)
=800*(7/2)+100*(7/2)+12*(7/2)
=(800+100+12)*(7/2)
=912*(7/2)
=456*7
=3192

Answer 2

解法1
(100+200+300+400+500+600+700)+(20+30+40+50+60+70+80)+(3+4+5+6+7+8+9)
=(100+700)*(7/2)+(20+80)*(7/2)+(3+9)*(7/2)
=800*(7/2)+100*(7/2)+12*(7/2)
=(800+100+12)*(7/2)
=912*(7/2)
=456*7
=3192
解法2
(123+789)/2*2+(234+678)*2/2+(345+567)*2/2+456
=456*2+456*2+456*2+456
=456*(2+2+2+1)
=456*7

追问

不能做加法

Answer 3

123+234+345+456+567+678+789=
=（123+789）+（234+678）+（345+567）+456
=912×3+456
=2736+456
=3192

Answer 4

4104