Виконати дії : 1/3 + 2/7+ 17/21=3/8 - 1/12 + 13/24=2/11 + 8/33 + 15/33=

1/3 + 2/7+ 17/21= 7/21 + 6/21 + 17/21 = 30/21 = 1целая 9/21 = 1цел. 3/7

3/8 - 1/12 + 13/24= 9/24 - 2/24 + 13/24 = 20/24 = 5/6

2/11 + 8/33 + 15/33= 6/33 + 23/33 = 29/33