title: How to use recursive in Haskell
body: <p>I'm trying to understand how recursion works in haskell, I'm trying to do a function that multiply using a sum</p>
  <p>Something like 4 * 5 = 4 + 4 + 4 + 4 + 4</p>
  <p>My current function is</p>
  <pre><code>multiplicacao a b 
      | b == 1 = a 
      | otherwise = multiplicacao (a + a) (b-1)
  </code></pre>
  <p>if I try to do multiplicacao 7 3 it returns 28</p>