Displaying results with a decimal place of two. Forcing decimal place.

Question

Hi there,
Im writing a simple calculation device.
You input one digit and press one of two buttons to multiply it by a certain number and then the result is displayed. The result is displyed hiding the result of the button you didn't press and visa versa.
I am having a problem displaying the result with a constant two decimal place.
I am using strings and thus don't know how to do this.
Here is my code:
import flash.events.MouseEvent;
//restrict the input textfield to only numbers
txtinput.restrict = "0-9";
//restrict the input textfield to only two characters
txtinput.maxChars = 6;
// event listeners
btnW.addEventListener(MouseEvent.CLICK, WHandler);
btnC.addEventListener(MouseEvent.CLICK, CHandler);
btnW.addEventListener(MouseEvent.CLICK, hideC);
btnC.addEventListener(MouseEvent.CLICK, hideW);
//functions
function WHandler (e:MouseEvent):void
          //white calculation
          var answerW:Number = Number(txtinput.text) * Number(0.90);
          txtWResult.text = answerW.toString();
function CHandler (e:MouseEvent):void
          //colour calculation
          var answerC:Number = Number(txtinput.text) * Number(0.99);
          txtCResult.text = answerC.toString();
function hideC (e:MouseEvent):void
          //Hide colour result
          txtCResult.visible = false;
          txtWResult.visible = true;
function hideW (e:MouseEvent):void
          //Hide white result
          txtWResult.visible = false;
          txtCResult.visible = true;
After having a look online I have found these two resources:
http://helpx.adobe.com/flash/kb/rounding-specific-decimal-places-flash.html
and
http://stackoverflow.com/questions/11469321/decimals-to-one-decimal-place-in-as3
But I am confused when combining these techniques with strings.
Any help would be greatly appreciated,
Thanks in advance
Mr B

Answer 1

Use the toFixed() method of the Number class instead of the toString() method.  The result of it is a String with the number of decimal places you specify.
          var answerW:Number = Number(txtinput.text) * Number(0.90);
          txtWResult.text = answerW.toFixed(2);
          var answerC:Number = Number(txtinput.text) * Number(0.99);
          txtCResult.text = answerC.toFixed(2);