Display var in text

ok i use to know this but its been i while since i messed with flash and i cant find an old file that has this nor could i find a tut or topic to help…

so i have _root. and in _root is a movie called score
there is a button on root that i want to where on click set var num1 to 20 and then have the number 20 show up in the score movie… i tried making a text box and putting num1 in the var then having the button have on release set num1, 20 but that didnt update the text box to display 20