7/12 - 1/3 / 1/2-2/5
(7/12 - 1/3) : (1/2 - 2/5) = 2 1/2 1) 7/12 - 1/3 = 7/12 - 4/12 = 3/12 = 1/4 2) 1/2 - 2/5 = 5/10 - 4/10 = 1/10 3) 1/4 : 1/10 = 1/4 * 10/1 = 10/4 = 2 2/4 = 2 1/2
Спс