12+23+34+45+56+67+78+89-(1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9)
=(12-2)+(23-3)+(34-4)+(45-5)+(56-6)+(67-7)+(78-8)+(89-9)-(1+2+3+4+5+6+7+8)
=10+20+30+40+50+60+70+80-36
=360-36
=324
哦耶
12+23+34+45+56+67+78+89-(1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9)
=(12-2)+(23-3)+(34-4)+(45-5)+(56-6)+(67-7)+(78-8)+(89-9)-(1+2+3+4+5+6+7+8)
=10+20+30+40+50+60+70+80-36
=360-36
=324
哦耶