max=20; 
answer = Math.floor(Math.random()*max)+1; 
left = Math.floor(Math.random()*answer); 
right = answer - left; 
equation = left+" + "+right+" = "; 
key = (answer*2)+1; answerkey = "<input type=hidden name=EQUATION value="+key+" >"; 
document.write(equation); 
document.write(answerkey);