[tex]\dfrac{1}{2}-\dfrac{1}{4} =\dfrac{1\cdot2}{2\cdot2}-\dfrac{1}{4} = \dfrac{2}{4}-\dfrac{1}{4} = \dfrac{1}{4}[/tex]
[tex]4\dfrac{1}{4}-\dfrac{1}{2} = \dfrac{4\cdot4+1}{4} -\dfrac{1\cdot2}{2\cdot2} = \dfrac{17}{4}-\dfrac{2}{4} = \dfrac{15}{4} = 3\dfrac{3}{4}[/tex]
