[tex]1 \times \frac{1}{4} = \frac{1}{4} [/tex]
[tex] \frac{1}{2} \times \frac{4}{1} = 1 \times 2 = 2[/tex]
[tex] \frac{5}{4} \times \frac{4}{1} = 5 \times 1 = 5[/tex]
[tex] \frac{11}{4} \times \frac{4}{1} = 11 \times 1 = 11[/tex]
Myślę że pomogłem ;)