function randomCFProblem(form) {
 	var theCF1 = ((Math.round(Math.random()*5)) + 1)*100;
 	var theCF2 = ((Math.round(Math.random()*5)) + 1)*100; 
 	var theCF3 = ((Math.round(Math.random()*5)) + 1)*100; 
 	var theCF4 = ((Math.round(Math.random()*5)) + 1)*100;  
 	var theNR = (Math.round((Math.random()*2000)+1)/100); 
 	form.Year1.value="" + theCF1;
 	form.Year2.value="" + theCF2;
 	form.Year3.value="" + theCF3;
 	form.Year4.value="" + theCF4; 
 	form.NRInput.value="" + theNR; 
 	form.PVOutput.value="";
 }
 
 function findPVCF(form) {
 	var theCF1 = form.Year1.value;
 	if (!isPositiveNumber(theCF1)) {
 		return false;
 	}
 	var theCF2 = form.Year2.value;
 	if (!isPositiveNumber(theCF2)) {
 		return false;
 	}
 	var theCF3 = form.Year3.value;
 	if (!isPositiveNumber(theCF3)) {
 		return false;
 	}
 	var theCF4 = form.Year4.value;
 	if (!isPositiveNumber(theCF4)) {
 		return false;
 	}
 	var theNR = form.NRInput.value;
 	if (!isPositiveNumber(theNR)) {
 		return false;
 	}
 	var thePV = theCF1/Math.pow((1 + theNR/100),1);
 	thePV += theCF2/Math.pow((1 + theNR/100),2);
 	thePV += theCF3/Math.pow((1 + theNR/100),3);
 	thePV += theCF4/Math.pow((1 + theNR/100),4);
 	form.PVOutput.value = "" + Math.round(thePV*100)/100;
 	return true;
 }
 
 function findFVCF(form) {
 	var theCF1 = form.Year1.value;
 	if (!isPositiveNumber(theCF1)) {
 		return false;
 	}
 	var theCF2 = form.Year2.value;
 	if (!isPositiveNumber(theCF2)) {
 		return false;
 	}
 	var theCF3 = form.Year3.value;
 	if (!isPositiveNumber(theCF3)) {
 		return false;
 	}
 	var theCF4 = form.Year4.value;
 	if (!isPositiveNumber(theCF4)) {
 		return false;
 	}
 	var theNR = form.NRInput.value;
 	if (!isPositiveNumber(theNR)) {
 		return false;
 	}
 	var thePV = theCF1*(Math.pow((1 + theNR/100),3));
 	thePV += theCF2*(Math.pow((1 + theNR/100),2));
 	thePV += theCF3*(1 + theNR/100);
 	thePV += theCF4*1.0;
 	form.PVOutput.value = "" + Math.round(thePV*100)/100;
 	return true;
 }
 
 function isPositiveNumber(inputStr) {
 	for (var i = 0; i < inputStr.length; i++) {
 		var oneChar = inputStr.substring(i,i+1);
 		if (((oneChar >= "0") && (oneChar <= "9")) || (oneChar == ".")) {
 		
 		} else {
 			alert("Please make sure that only numbers are input.");
 			return false;
 		} 
 	}
	return true;
 }