(1/12 + 1/6) : ( 3/8 - 1/4) = (1/12 + 2/12) : ( 3/8 - 2/8) = 3/12 : 1/8 = 1/4 х 8/1 = 2.
( 1 - 4/9) : (1/3 - 1/4) = 5/9 : ( 4/12 - 3/12) = 5/9: 1/12 = 5/9 х 12/1 = 20/3 = 6 2/3.
(1/3 - 5/16):(1/6 - 1/8)= (16/48 - 15/48):(4/24-3/24)= 1/48:1/24= 1/48 х 24/1 = 1/2.
(5/7-2/3):(4/9-5/12) = (15/21-14/21):(16/36-15/36)= 1/21:1/36= 1/21х36/1=36/21=12/7= 1 5/7.
Б)
1)14мин4с>844c
дальше просто ставлю знак по порядку
2)>
3)<
4)>
5)<
6)<