Question

1/2 - 1/3 - 1/4 + 5/2 - 7/3 + 9/4

Answer 1

   1/2-1/3-1/4+5/2-7/3+9/4

=6/12-4/12-3/12+30/12-28/12+27/12

=(6-4-3+30-28+27)/12

=28/12=7/3

 

Answer 2

Answer 3

Ta có: \(\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{5}{2}-\dfrac{7}{3}+\dfrac{9}{4}\)

\(=\left(\dfrac{1}{2}+\dfrac{5}{2}\right)-\left(\dfrac{1}{3}+\dfrac{7}{3}\right)+\left(\dfrac{9}{4}-\dfrac{1}{4}\right)\)

\(=\dfrac{6}{2}-\dfrac{8}{3}+\dfrac{8}{4}\)

\(=3+2-\dfrac{8}{3}\)

\(=5-\dfrac{8}{3}=\dfrac{15}{3}-\dfrac{8}{3}=\dfrac{7}{3}\)