沒算過economic wrote:12345678987654321*(1+2+3+4+5+6+7+8+9+8+7+6+5+4+3+2+1)=X的平方,求X 試解用 1,2 去排121*(1+2+1)=48422的平方484同理1 ~9x應該是999999999
=======================================原題目1+4=5 = (1+4)2+5=12 = (1+4+2+5)3+6=21 = (1+4+2+5+3+6)8+11=?=======================================Sol:1+4=52+5=123+6=217+10=38 =(1+4+2+5+3+6+7+10)8+11=57 =(1+4+2+5+3+6+7+10+8+11)9+12=78所以小弟的想法是 57 ,不知對不對