(2又2/7 + 4又5/6 + 7又5/7 + 5又1/6)*(2-2/11)

问题描述:

(2又2/7 + 4又5/6 + 7又5/7 + 5又1/6)*(2-2/11)
用简便方法计算.

(2又2/7 + 4又5/6 + 7又5/7 + 5又1/6)*(2-2/11)
=【(2又2/7+ 7又5/7) + (4又5/6+ 5又1/6)】*(2-2/11)
=[10+10]×(2-2/11)
=20×2-20×2/11
=40-40/11
=40-3-7/11
=36又4/11