title: Scheme Sum from a to b Iteratively
body: <p>I am trying to write a procedure that adds all the numbers between a and b. For example if a=1 and b=5, the procedure would add 1+2+3+4+5. Here's what I have so far. I want to write this iteratively. Thanks!</p>
  
  <pre><code>(define (sum term a next b)
    (define (iter a result)
      (if (&gt; a b)
          sum
          (iter ?? ??)))
    (iter ?? ??))
  </code></pre>