title: How get the total sum of NSNumber's from a NSArray?
body: <p>I have a large <code>NSArray</code> containing <code>NSNumbers</code> like <code>3, 4, 20, 10, 1, 100,</code> etc...</p>
  
  <p>How do I get the total sum of all these NSNumbers <code>(3 + 4 + 20 + 10 + 1 + 100 + etc...)</code> as one total <code>NSInteger</code>?</p>
  
  <p>Thank you!</p>