Выполнить действие: а) 9 - 11/12; б) 2/3 + 4 3/5; в) 5 7/8 + 2 5/12; г) 20 5/6 - 2 3/4; !

1) 9 - 11/12 = 8 12/12 - 11/12 = 8 1/12
2) 2/3 + 4 3/5 = 10/15 + 4 9/15 = 4 19/15 = 5 4/15
3) 5 7/8 + 2 5/12 = 5 21/24 + 2 10/24 = 7 31/24 = 8 7/24
4) 20 5/6 - 2 3/4 = 20 10/12 - 2 9/12 = 18 1/12