splitting column

declare @a varchar(50)='$400 per FBD'
Select @a

sometimes the column value is like this

declare @a varchar(50)='$2000 x FBDs /5'
Select @a

At the end I'm interested in seeing like this 

amount   Divider

400             1   (As there is no divider like as in second example)

2000           5

Note.The length is not fixed. I cannot use substring.

Any help is highly appreciated.