Question

Thực hiện phép tính

\(\dfrac{5}{21}+0,5-\dfrac{19}{23}+\dfrac{16}{21}-\dfrac{4}{23}\)

Answer 1

\(\dfrac{5}{21}+0,5-\dfrac{19}{23}+\dfrac{16}{21}-\dfrac{4}{23}\)

\(=\left(\dfrac{5}{21}+\dfrac{16}{21}\right)-\left(\dfrac{19}{23}+\dfrac{4}{23}\right)+0,5\)

\(=1-1+0,5\)

\(=0,5\)

Answer 2

\(\dfrac{5}{21}+0,5-\dfrac{19}{23}+\dfrac{16}{21}-\dfrac{4}{23}\)

=\(\dfrac{5}{21}+\dfrac{1}{2}-\dfrac{19}{23}+\dfrac{16}{21}-\dfrac{4}{23}\)

=\(\left(\dfrac{5}{21}+\dfrac{16}{21}\right)+\left(\dfrac{-19}{23}+\dfrac{-4}{23}\right)+\dfrac{1}{2}\)

= 1 + (-1) +\(\dfrac{1}{2}\) = 0 + \(\dfrac{1}{2}\) =\(\dfrac{1}{2}\)