Problem when i try subtract a variable.

Hello!

I´m making the health system of my player but i have a problem when i try to subtract a variable… here is the code:

using UnityEngine;
using System.Collections;

public class SaludEnemigo : MonoBehaviour {

	public int salud = 100;
	public int cursalud = 100;
	public int dano = 10;
	
	// Use this for initialization
	void Start () {
	   
	
	}
	
	// Update is called once per frame
	void Update () {
		
		if (cursalud < 1)
		  cursalud = 1;
		
		if (cursalud > 100)
		  cursalud = 100;
	
	}
	
	void HacerDano(){
		cursalud - dano;  //here is the problem
	}
	
	void OnTriggerEnter (Collider dagger){
		
		HacerDano();
		
	}
	
	
}

The script is in spanish i make a few traductions:
salud = health
cursalud = current health
dano = damage
HacerDano = make damage

And here is the problem that reports the editor:

Assets/Scripts/SaludEnemigo.cs(28,32): error CS0201: Only assignment, call, increment, decrement, and new object expressions can be used as a statement

See you!

AW:i now that the script is really “basic” but i´m starting with the Triggers .

current health = current health - damage
or
current health -= damage

yes it wotks thx!