Сколько двенадцатых долей содержится в 1/4, 1/6, 3/4, 5/6, 2/3?

(1•3)/(4•3) = 3/12;
(1•2)/(6•2) = 2/12;
(3•3)/(4•3) = 9/12;
(5•2)/(6•2) = 10/12;
(2•4)/(3•4) = 8/12.