Object reference not set to an instance of an object c#

Questions & Answers
1

every time i play my game then console print thousand time this message
NullReferenceException: Object reference not set to an instance of an object
ScoreManager.Update () (at Assets/Script/ScoreManager.cs:25)

What i don now ? in below i add my script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class ScoreManager : MonoBehaviour {

public static int score = 0 ;

Text scoreText;

// Use this for initialization
void Start () {
	scoreText = GetComponent<Text>();

}

// Update is called once per frame
void Update ()
{
	if (score < 0)
		score = 0;

	scoreText.text = "" + score;

}

public static void AddPoints (int pointAdd){
score += pointAdd;
}

public static void Reset ()
{
	score = 0;
}

}

2

Are the Text component attached to the same gameobject? Otherwise you must write:

scoreText = GameObject.Find("NameofGBWhereComponentIs").GetComponent<Text>();

Or, you can reference the game Object in code:

public Text scoreText;

and drag the text component to it in the inspector.