1+2+3········+31+32+33=17 곱 하기 33,1-3+2-6+3-9+··········+31-93+32-96+33-99 의 값 을 구하 고,

1+2+3········+31+32+33=17 곱 하기 33,1-3+2-6+3-9+··········+31-93+32-96+33-99 의 값 을 구하 고,

1-3+2-6+3-9+········+31-93+32-96+33-99
=1+2+3+····+33-(3+6+9+····+99)
=1+2+3+····+33-3*(1+2+3+····+33)
=-2*(1+2+3+····+33)
=-2*17*33