Best way to animate incrementing/decrementing values ?

I am trying to animate text where numerical values don't simply just go from value A to value B but increment/decrement quickly over a set amount of time (meaning a set amount of frames). For example, if the game is at 30 frames per seconds and I go from 10 hit points to 40 points, I would like the hit point counter to show each increment of the hit point value (31, 32, 33 ... 38, 39, 40) over a 1 second period.

I created a simple script that can be attached to any gameObject that wants animated text:

using UnityEngine; using System.Collections;

 public class TextUpdater : MonoBehaviour {
 
     private UILabel _label;
     private int _initialValue = 0;
     private int _finalValue = 0;
     private string _format = null;
     private int _duration = 0;
 
     private float timeElapsed = 0.0f;
 
     public void Set(UILabel label, int initialValue, int finalValue, int duration, string format = null)
     {
         _label = label;
         _initialValue = initialValue;
         _finalValue = finalValue;
         _duration = duration;
         _format = format;
 
         _label.text = _initialValue.ToString(_format);
     }
 
     void Update()
     {
         timeElapsed += Time.deltaTime;
 
         if(timeElapsed > _duration)
         {
             _label.text = _finalValue.ToString(_format);
             Destroy(this);
         }
         else
         {
             float value  = Mathf.Lerp(_initialValue,_finalValue, timeElapsed/_duration);
             _label.text = value.ToString(_format);
         }
         
     }
 }

And here is a simple use of the script :

 using UnityEngine;
 using System.Collections;
 
     public class hitPointHuD : MonoBehaviour
     {
         private UILabel __hitpointsLabel;
         private int _hitpoints = -1;
         
         // ------------------------------------------------------------
         // Get reference to instances
         // ------------------------------------------------------------
         void Start ()
         {
             __hitpointsLabel = GetComponent<UILabel>();
         }
         
         // ------------------------------------------------------------
         // Update label if hitpoint changes
         // ------------------------------------------------------------
         void Update ()
         {
             if (_hitpoints != Level.Instance.hitpoints)
             {
                 int previousHP = _hitpoints;
                 _hitpoints = Level.Instance.hitpoints;
     
                 gameObject.AddComponent<sbLabelUpdater>().Set(__hitpointsLabel, previousHP, _hitpoints, 2, "N0");
             }
         }
     }

Now this code works fine and it gives me the exact effect I want. What I do not like is the division ("timeElapsed/_duration") in the update call. Being where it is, this division will occur every frame for every UILabel that is being updated. I don't see how I could use Lerp without the ratio I get from the division. Do note that I do not absolutely want to use Lerp at all costs, it was simply the 1st solution that came to my mind.

I know I am not the first to want to create this effect... yet since it does not have an official name it has been quite hard to find examples. Does anyone know a better way to create this effect ?

Thanks !