计算(1+19\39×1)+(1+19\39×2)+(1+19\39×3)+……+(1+19\39×12用简便方法计算,

问题描述:

计算(1+19\39×1)+(1+19\39×2)+(1+19\39×3)+……+(1+19\39×12用简便方法计算,