title: I need a good analogy to make sense of Class methods vs. instance methods
body: <p>Im getting fairly confused as the book im reading is delving into the NSNumber class and talks about all the  different methods you can call on it. I have a couple questions:</p>
  
  <p>1.) Do you not have to call a typical alloc or init on foundation classes?</p>
  
  <p>2.)in what cases would you use, say, numberWithChar: as opposed to initWithChar (i think this is the part that is messing me up the most, not really sure im groking this concept on the level i need to be, if you folks could break it down for me I think it would really help me get over this humper-roo.</p>
  
  <p>Thanks,</p>
  
  <p>Nick</p>