简便运算:31又1/3×41又1/2-11又1/3×41又1/2×2-9.5×11又1/3

问题描述:

简便运算:31又1/3×41又1/2-11又1/3×41又1/2×2-9.5×11又1/3

"31又1/3×41又1/2-11又1/3×41又1/2×2-9.5×11又1/3=(31又1/3-11又1/3)×41又1/2-(41又1/2+9.5)×11又1/3=20×41又1/2-51×11又1/3=830-578=252