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

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

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

\(=0,5\)

2,\(\frac{27}{23}+\frac{5}{21}-\frac{4}{23}+\frac{6}{21}+\frac{1}{2}\)

\(=\frac{27-4}{23}+\frac{5+6}{21}+\frac{1}{2}\)

\(=1+\frac{11}{21}+\frac{1}{2}\)

\(=\frac{42+22+21}{42}\)

\(=\frac{85}{42}\)

=27/23+5/21-4/23+1/2+16/21

=682/483-4/23+1/2+16/21

=26/21+1/2+16/21

=5/2

=1+4/23-4/23+5/21+16/21+1/2

=1+1+1/2

=5/2

\(\dfrac{27}{23}\) + \(\dfrac{5}{21}\) - \(\dfrac{4}{23}\) + \(0,5\) + \(\dfrac{16}{21}\)

= [ \(\dfrac{27}{23}\) - \(\dfrac{4}{23}\) ] + [ \(\dfrac{5}{21}\) + \(\dfrac{16}{21}\) ] + 0,5

=  1 + 1 + 0,5 

=  2 + 0,5

=  2,5

\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)

= \(\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)-0,5\)

= 1+1-0,5

=1,5

Kết hợp các phân số ta có :

\(\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\)

\(=1+1+0,5=2,5\)

\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)

\(=\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\)

\(=1+1+0,5=2,5\)

\(1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}\)

= \(\left(1\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+0,5\)

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

= \(2+0,5\)

= \(2,5\)

Chúc bạn học tốt!