Question

\(\left(-\frac{1}{2}\right)+\left(-\frac{1}{9}\right)-\left(-\frac{3}{5}\right)+\frac{1}{2006}-\left(-\frac{2}{7}\right)\)

Answer 1

\(\left(-\frac{1}{2}\right)+\left(-\frac{1}{9}\right)-\left(-\frac{3}{5}\right)+\frac{1}{2006}-\left(-\frac{2}{7}\right)\)

\(=\left(-\frac{1}{2}\right)-\frac{1}{9}+\frac{3}{5}+\frac{1}{2006}+\frac{2}{7}\)

\(=\left[\left(-\frac{1003}{2006}+\frac{1}{2006}\right)\right]+\left[\left(-\frac{5}{45}+\frac{27}{45}\right)\right]+\frac{2}{7}\)

\(=-\frac{1002}{2006}+\frac{22}{45}+\frac{2}{7}\)

\(=-\frac{501}{1003}+\frac{154}{315}+\frac{90}{315}\)

\(=-\frac{501}{1003}+\frac{244}{315}\)

\(=-\frac{157815}{315945}+\frac{244732}{315945}=\frac{86917}{315945}\approx0,28\)

P/s : Vì bài này số quá xấu nên mình đổi ra số thập phân cho gọn nhé ....