How can I reference "score" in one script and then use it in another?

Hi, beginner coder here and I'm working on a script for a breakout like game and I'm currently working on the score... However I have hit a brick wall and I cannot seem to fix it. Firstly, I apparently haven't referenced "score" In my GameManager script, although I think I have. Would appreciate any help, thanks in advance!

(Brick Script)

 `using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class brick : MonoBehaviour
 {
     public GameManager GM;
     public AudioSource Block_Destroy;
     private int block_health = 1;
     private int score_multiplier = 1;
     void Start (){
         GM = GameObject.FindWithTag("GameManager").GetComponent<GameManager>();
         switch (gameObject.tag)
         {
             case "Purple":
                 block_health = 1;
                 score_multiplier = 1;
                 break;
             case "Blue":
                 block_health = 1;
                 score_multiplier = 1;
                 break;
             case "Yellow":
                 block_health = 2;
                 score_multiplier = 2;
                 break;
             case "Green":
                 block_health = 2;
                 score_multiplier = 2;
                 break;
         }
     }





 void Update ()
 {
 
 }

 void OnCollisionEnter2D(Collision2D col){
     if (col.gameObject.tag == "Ball"){
         Block_Destroy.Play(); 
         block_health--;
     }
     if (block_health <= 0){

        GM.scoreText += 1 * score_multiplier;
         Destroy(gameObject);
     }

     }
 }`

(GameManager Script)

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 
 public class GameManager : MonoBehaviour 
 {
 
     public Text score_count;
     public Text lives_count;
 
     static public int score = 0;
     static public int lives = 3;
     
 
     void start ()
     {
     }
 
     void update()
     {
 
         score_count.text = score.ToString();
         lives_count.text = lives.ToString();
 
     }
 }