How to make the value decrease?

programming flash
1

Heya there just havig a stupid problem where the health on my game increases on my game instead of decreases when the player is hit.

here is the source code

HUD.as (Scoreboard)


 
        private var stageRef:Stage;
        public var s_score:Number = 0;
        public var s_kills:Number = 0;
        public var s_health:Number = 0;
 
        
 
           
            health.text = "100";
 
            
       
 
        public function updateHits(value:Number) : void
        {
            s_health += value;
            health.text = String(s_health);
        }
 
        
 
    }
 
}

engine.as (game engine)

private function shipHit(e:Event) : void
        {
            theHUD.updateHits(1); 
        }

thanks for any help