What does NaN mean? How do you fix this?

[RaynbowzRule]

Hello, I'm having trouble with my coding. Upon clicking on a button I would like my movie clip to appear and subtract 1 from my variable. My variable is called 'woo'. My movie clip is called 'mydays'. Here is the code:

on (release) {
	if (_root.mydays._visible) {
		_root.mydays._visible = false;
	} else {
		_root.mydays._visible = true;
	}
}
on (release) {
	if (day < 30) {
	day += 1;
	hp += 50;
} else if (day = 30) {
	gotoAndPlay ("endofgame")
}
}

on (release) {
	_root.mydays. woo -= 1;
}

Every time I test my button, my movie clip appears as I want it to but the variable says NaN. What does this mean? How can I fix this?

[pistelli]

NaN means "not a Number".
Is your variable inside your MC??
Can´t understand this code.
Attach the file.

[rynoe]

You need to assign a number to a variable before you try to use it in math.

_root.mydays.woo =100;


on (release) {
	if (_root.mydays._visible) {
		_root.mydays._visible = false;
	} else {
		_root.mydays._visible = true;
	}
}
on (release) {
	if (day < 30) {
	day += 1;
	hp += 50;
} else if (day = 30) {
	gotoAndPlay ("endofgame")
}
}

on (release) {
	_root.mydays.woo -= 1;
}

[RaynbowzRule]

Yes my variable is inside my movie clip. The file is too big for me to attach it.

[RaynbowzRule]

Never mind, I figured out what was wrong. Thanks for helping!