1+11+21+31+41+51+61+71+81+91=
问题描述:
1+11+21+31+41+51+61+71+81+91=
答
1+11+21+31+41+51+61+71+81+91=(1+91)+(11+81)+.+(41+51)=92*5=460
1+11+21+31+41+51+61+71+81+91=
1+11+21+31+41+51+61+71+81+91=(1+91)+(11+81)+.+(41+51)=92*5=460