function MathRandom () {
	var p_random = new Array();
	p_random[0] = "r-1";
	p_random[1] = "r-2";
	p_random[2] = "r-3";
	var Content = Math.floor(Math.random() * p_random.length);
	document.getElementById(p_random [Content]).style.display = 'block' 
}