Should be something like this:
Create a global variable DiceRoll
Add the function object to your game
triggered event (on sprite clicked?)
- system set variable DiceRoll = int(random(1,111))
- Function call "DiceAction" with parameter0 DiceRoll
on function "DiceAction"
- Function if parameter0 is < 50
> (add the action you'd like)
- Function if parameter0 > 49
- Function if parameter0 < 100
> (add the action you'd like)
- Function if parameter0 > 100
> (add the action you'd like)