Question

Tính hợp lí:

A=\(\dfrac{1}{2}-\left(\dfrac{-2}{5}\right)+\dfrac{1}{3}+\dfrac{5}{7}-\left(\dfrac{-1}{6}\right)+\left(\dfrac{-4}{35}\right)+\dfrac{1}{41}\)

Answer 1

A=\(\dfrac{1}{2}\)-\(\left(\dfrac{-2}{5}\right)\)+\(\dfrac{1}{3}\)+\(\dfrac{5}{7}\)-\(\left(\dfrac{-1}{6}\right)\)+\(\left(\dfrac{-4}{35}\right)\)+\(\dfrac{1}{41}\)

=\(\dfrac{1}{2}\)+\(\dfrac{2}{5}\)+\(\dfrac{1}{3}\)+\(\dfrac{5}{7}\)+\(\dfrac{1}{6}\)-\(\dfrac{4}{35}\)+\(\dfrac{1}{41}\)

=\(\left[\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6}\right]\)+\(\left[\dfrac{2}{5}+\dfrac{5}{7}-\dfrac{4}{35}\right]\)+\(\dfrac{1}{41}\)

= 1 + 1 +\(\dfrac{1}{41}\)

= \(\dfrac{83}{41}\)