Пошаговое объяснение:
13/52 = 1/4
21/56 = 3/8
0,375 = 375/1000 = 3/8
17/51 = 5/15
51 = 3 * 17 * 1
15 = 3 * 5 * 1
НОК = 3 * 17 * 5 * 1 = 255
255 : 51 = 5
255 : 15 = 17
17 * 5 85 5 * 17 85
= и =
51 * 5 255 15 * 17 255
85 = 85
