title: Javascript: Changing a positive number to a negative?
body: <p>I have been trying to do the following - change a positive to a negative number.</p>
  
  <p>It appears there are a number of ways to do this. There is the standard</p>
  
  <pre><code>x *= -1
  </code></pre>
  
  <p>or just placing a negative sign in front the variable i.e if x = 5, then -x is equal to -5.</p>
  
  <p>This seems a great shorthand but wanted to know what the difference is, I can't find any documentation regarding this shorthand on MDN.</p>
  
  <p>I assume there are other ways too.</p>
  
  <p>Probably a basic question but it is annoying not understanding this apparent shorthand.</p>
  
  <p>Any ideas ?</p>