31又3/1乘以41又2/1减11又3/1乘以41又2/1乘以2 减9又2/1乘以11又3/1

问题描述:

31又3/1乘以41又2/1减11又3/1乘以41又2/1乘以2 减9又2/1乘以11又3/1

他们之间有括号吗?
如果没有答案为:252
简便过程如下:
原式=31 1/3×41 1/2-11 1/3×41 1/2-(11 1/3×41 1/2+9 1/2×11 1/3)
=41 1/2×(31 1/3-11 1/3)-11 1/3×(41 1/2+9 1/2)
=41 1/2×20-11 1/3×51
=83/2×20-34/3×51
=83×10-34×17
=252