<!--
var varA;
var varB;
var varC;
var varD;
var varE;
var varF;
var varX;
var varY;

var curA;
var curB;
var curC;
var curD;
var curE;
var curF;

var CorrectCount=0;
var NumberAttempted=0;

function NewProblem() {
Status.innerText = "Answers not Checked" 
Simul.FirstMult.value=1;
Simul.SecondMult.value=1;
Simul.XMult.value=0;
Simul.YMult.value=0;
varA = eval(Math.floor(Math.random()*20)+"-10");
varB = eval(Math.floor(Math.random()*20)+"-10");
varX = eval(Math.floor(Math.random()*20)+"-10");
varY = eval(Math.floor(Math.random()*20)+"-10");

if (varA==0) varA=10;
if (varB==0) varB=10;
if (varX==0) varX=10;
if (varY==0) varY=10;

varC = varX*varA + varY*varB;

do {
varD = eval(Math.floor(Math.random()*20)+"-10");
varE = eval(Math.floor(Math.random()*20)+"-10");
if (varD==0) varD=10;
if (varE==0) varE=10;
} while (varA/varB==varD/varE);

varF = varX*varD + varY*varE;

FirstForm.innerText = varA+"x + "+varB+"y = "+varC
SecondForm.innerText = varD+"x + "+varE+"y = "+varF

Recalculate();
Simul.btnCheck.disabled=false;

}

function Recalculate(){
curA = varA*Simul.FirstMult.value;
curB = varB*Simul.FirstMult.value;
curC = varC*Simul.FirstMult.value;
curD = varD*Simul.SecondMult.value;
curE = varE*Simul.SecondMult.value;
curF = varF*Simul.SecondMult.value;

FirstFormMult.innerText = curA+"x + "+curB+"y = "+curC;
SecondFormMult.innerText = curD+"x + "+curE+"y = "+curF;

}

function Add(){
Recalculate();
var varAD = eval(curA+curD)
var varBE = eval(curB+curE)
var varCF = eval(curC+curF)

if (varAD!=0 && varBE!=0) FormAdd.innerText = eval(curA+curD)+"x + "+eval(curB+curE)+"y = "+eval(curC+curF);
else {
if (varAD==0 && varBE!=0) FormAdd.innerText = eval(curB+curE)+"y = "+eval(curC+curF);
else                      FormAdd.innerText = eval(curA+curD)+"x = "+eval(curC+curF); } }

function Check(){
NumberAttempted++;
var studentAnswerX = eval(Simul.XMult.value)
var studentAnswerY = eval(Simul.YMult.value)
if (studentAnswerX==varX && studentAnswerY==varY) { CorrectCount++; Status.innerText = "CORRECT!" }
else { Status.innerText = "Incorrect. x="+varX+" y="+varY; }

if (NumberAttempted>=10) Simul.btnNew.disabled=true;
Simul.btnCheck.disabled=true;
NumberCorrect.innerText = "Correct: "+CorrectCount;

}

function FormatNumeric(Field){
var numbers="-0123456789";
var character=""
var temp=""
temp=Field.value
if(temp.length>1) {
  for(j=0;j<temp.length;j++) {
     character=temp.substring(j,j+1);
     if(numbers.indexOf(character)==-1) while(Field.value.indexOf(character)!=-1) Field.value=Field.value.replace(character,'');} }
else {if(numbers.indexOf(temp)==-1) Field.value=Field.value.replace(temp,'');}
}



-->