1-3+2-6+3-9+4-12+…+31-93+32-96
问题描述:
1-3+2-6+3-9+4-12+…+31-93+32-96
答
1-3+2-6+3-9+4-12+…+31-93+32-96= (1-3)+(2-6)+(3-9)+(4-12)+…+(31-93)+(32-96)= (-2)+(-4)+(-6)+(-8)+ .+(-62)+(-64)= (-2)*(1+2+3+4+ .+31+32)= (-2)*(1+32)*32/2= (-1)*33*32= -1056