you need to first cast the number into a string format and then you need to extract its middle substring.
in this example i used 2 text objects, the first one is to show the original value in a string format (i stored the actual number in a variable inside the text object) and the second one is to show the extracted number but you can just as easily have done that with only one string object.
the middle substring method comes from the system object in this format:
Mid(String, Start, Count)
"Mid" is pretty obvious, it's the name of the method that's being called.
"String" is where you put the string, it can either be provided explicitly or it can come from an object as i have done in the picture but those aren't the only ways.
"Start" is the position you would want to substring to start extracting from beginning at the left.
"Count" is the number of characters you want to extract beginning from the start position.
the only thing you will have to be careful of is the ordering of the actions because certain actions aren't possible without other actions having taken place first.
i'd put up a picture of the actual outcome at runtime but it isn't much to look at, it's just a window with "1558" in one spot and "5" in another. XD
other than that, just play around with that method if you don't quite understand my essay of an explanation. lol