Question

[Đào Thị Xuân Mỹ(Bé's Muỗi's )]

tính nhanh

\(\left(\frac{1999}{2011}-\frac{2011}{1999}\right)\)-\(\left(\frac{-12}{1999}-\frac{12}{2011}\right)\)

Answer 1

[Nguyễn Thị Thủy Tiên]

\(\left(\frac{1999}{2011}-\frac{2011}{1999}\right)-\left(\frac{-12}{1999}-\frac{12}{2011}\right)\)

= \(\frac{1999}{2011}-\frac{2011}{1999}+\frac{12}{1999}+\frac{12}{2011}\)

= \(\left(\frac{1999}{2011}+\frac{12}{2011}\right)-\left(\frac{2011}{1999}+\frac{-12}{1999}\right)\)

= \(\frac{2011}{2011}-\frac{1999}{1999}\)= 1-1 =0

Answer 2

[bímậtnhé]

\(=\frac{1999}{2011}-\frac{2011}{1999}+\frac{12}{1999}+\frac{12}{2011}=\frac{1999}{2011}+\frac{12}{2011}\)\(+\left(\frac{-2011}{1999}+\frac{12}{1999}\right)\)\(=1+\left(-1\right)=0\)