The below code shows how to use the class

import druva.NumberUtil;
trace(NumberUtil.isBetween(5, 10,100));
// 10

trace(NumberUtil.isBetween(5, 10,100, 50));
// 50

This is the actual class for validation

package druva{
	import flash.display.Sprite;

	public class NumberUtil extends Sprite {
		public function NumberUtil() {
		}

		public static function isBetween(number:Number, min:Number, max:Number, def:Number=0):Number {
				return ((number >= min ) && (number <= max )) ? number : ((def == 0) ? min : def);
		}

	}
}