function MyFunction1()
	{
	var w = parseFloat(document.form1.field1.value);
	var x = parseFloat(document.form1.field2.value);
	var y = parseFloat(document.form1.field3.value);
	if (isNaN(x))
		{
		alert("Not a Number")
		document.form1.field2.value = ""
		document.form1.field2.focus()
		}
	
	var z = w+x+y;
	var v = w*x*y;
	var u = w/x/y;
	var t = w-x-y;
	
	document.form1.field4.value=z
	document.form1.field5.value=v
	document.form1.field6.value=u
	document.form1.field7.value=t
	}