If you need to generate a random integer number within a range, you can use random() expression, for example:
Set r to int(random(10, 15))
This will produce one of these numbers - 10, 11, 12, 13, 14. Note, that it doesn't include 15.
EDIT: If you need to place something within 10px of Platform.x, you can use random(Platform.x-10, Platform.x+10)