б) 3/4 - 1/2 = 6/8 - 4/8 = 2/8 = 1/4
д) 5/9 - 5/12 = 20/36 - 15/36 = 5/36
з) 19/21 - 11/15 = 95/105 - 77/105 = 18/105 = 6/35
л) 11/21 - 2/35 = 55/105 - 6/105 = 49/105 = 7/15
б) 3/4 - 1/2 = 6/8 - 4/8 = 2/8 = 1/4
д) 5/9 - 5/12 = 20/36 - 15/36 = 5/36
з) 19/21 - 11/15 = 95/105 - 77/105 = 18/105 = 6/35
л) 11/21 - 2/35 = 55/105 - 6/105 = 49/105 = 7/15