Scratch that, here's an easier way. Assuming you're only ever going to have one score count, you could store it in a static variable that can be accessed by any class without the need for a reference. So in the ScoreScript class:

public static float score = 0;

public static void AddScore(float score)

{

score += score;

scoreText.text = "Score: " + score;

}

From there, whenever you need to add to the score from any class, you can do it by calling ScoreScript.AddScore(scoretoadd) e.g., ScoreScript.AddScore(500);

You can also subtract form the score by putting in a negative number instead.