Economics game

<html>
<head>
<style>

</style>
<script>
//Marcro economic variables
var intrest = 0.5;
var inflation = 3;
var unemplyment = 5;
function Run(){

if (inflation > 3){
inflation = Math.round(10*((2* inflation)/intrest + Math.random()))/10;
}
else{
inflation = Math.round(10*(4/intrest + Math.random()))/10;
}
unemployment = Math.round(10*( 2*intrest + Math.random()))/10;
update();
}

function update(){
     var x = document.getElementById('intrestrates');
     x.innerHTML = intrest + "%";
     var y = document.getElementById('generalpricelevel');
     y.innerHTML = inflation + "%";
     if (inflation > 3 || inflation < 1){y.style.color = "red";}
     else{y.style.color = "black";}
     var z = document.getElementById('unemployment');
     z.innerHTML = unemployment + "%";
     if (unemployment > 5){z.style.color = "red";}
     else{z.style.color = "black";}
}
function increaseintrest(){ intrest = intrest + 0.5; update(); }
function decreaseintrest(){ if (intrest > 0 ){intrest = intrest - 0.5;} update(); }
</script>
</head>
<body>
<div style="position:absolute;top:10px;right:100px;">
<input type="button" value="Next" onclick="Run();">
</div>
<center> <h1>Economics</h1></center>
<p id="ab" ><b>Notes</b> - The macro economic  dependent variables; inflation, unemployment, <br />
 - The macro economic independent variables; Intrest rates;</p>

<table id="eco" border="1" ><tr>
<td><h3>Intrest rates</h3></td><td><h3>Inflation</h3></td><td><h3>Unemployment</h3></td></tr>
<tr><td><x id="intrestrates">0.5%</x> <div style="text-align:right;" ><input type="button" value ="-" onclick="decreaseintrest();"><input type="button" value="+" onclick="increaseintrest();"></div></td><td id="generalpricelevel">3%</td><td><x id="unemployment" >5%</x></td></tr>
</table>
</body>
</html>