Math help PLS

I know this might not belong here, but I know alot of you are really smart so i must ask. It is somewhat belonging here, since this question will help me learn math which helps me get grades for med school! </p>

<p>"give a rough definition of what it means for a set to be countably infinate". </p>

<p>I have a small idea, but I really want to be sure before i hand it in. Can you help me out please?</p>

<p>nvm, the greg got it without yous!</p>

<p>YAY hahaha</p>