IncreaseScoreOverTime.cs

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

public class IncreaseScoreOverTime : MonoBehaviour
{
	//The text component that the score will be displayed on.
	[SerializeField]
	private Text _scoreText;

	//The time it will take to update the score.
	[SerializeField]
	private float _updateTime = 1f;
	//The current displayed score.
	private float _score;
	//The actual score.
	private float _updatedScore;

	//The coroutine used to update the score.
	private Coroutine _lerpScoreCoroutine;

	/// <summary>
	/// Starts the coroutine to update the score to the updated score.
	/// </summary>
	/// <param name="scoreMutation">The amount that is added to the score.</param>
	private void UpdateScore(float scoreMutation)
	{
		if (_lerpScoreCoroutine != null)
		{
			StopCoroutine(_lerpScoreCoroutine);
		}
		_updatedScore = _updatedScore + scoreMutation;
		_lerpScoreCoroutine = StartCoroutine(LerpScore());
	}

	/// <summary>
	/// Lerps the score from score to updated score and displays it on the text component.
	/// </summary>
	private IEnumerator LerpScore()
	{
		float elapsedTime = 0;

		while (elapsedTime < _updateTime)
		{
			_score = Mathf.Lerp(_score, _updatedScore, (elapsedTime / _updateTime));
			_scoreText.text = (Math.Round((decimal)_score, 0)).ToString();
			elapsedTime += Time.deltaTime;
			yield return new WaitForEndOfFrame();
		}
	}
}