12345678987654321×(1+2+3+4+5+6+7+8+9+…………+100)=12345678987654321×(1+100)×100÷2=12345678987654321×5050=62345678887654321050
答案是:62345678887654321050
原式=12345678987654321×5050=自己用电脑算去吧
62315678887654321050