title: Difference between (25) and @(25)
body: <p>I have been brushing up on my objective-c and one of the exercises that I am working on deals with UIInterpolatingMotionEffect objects. 2 properties from that class are <code>minimumRelativeValue</code> and <code>maximumRelativeValue</code>. In the exercise they have them as the following:</p>
  
  <pre><code>motionEffect.minimumRelativeValue = @(-25);
  motionEffect.maximumRelativeValue = @(25);
  </code></pre>
  
  <p>I know that in obj-c you use @ for the following (from wikipedia):</p>
  
  <pre><code>Used to avoid taking english words and making them reserved (for example, you can't have a variable called float in C/Objective-C because this is a reserved word).
  </code></pre>
  
  <p>With that being said, what would be the difference between using <code>@(-25)</code> and <code>(-25)</code> in the above example?</p>