As2 Question Button that counts read to understand

[Mancent]

Ok I want to make a button that changes a text to count 21+

so lets say we have our button

button.onRelease = function()
{


}

Ok lets say we have a dynamic text

button.onRelease = function()
{

ourtext.text ="0";

}

Ok every time I click the button I want the ourtext.text ="0";
to count + 21

so if i click it once is the ourtext.text ="21";
if I click it again its ourtext.text ="42";

and soon untill limit of 5000

How can I do that?