title: Convert a string equation to an integer answer
body: <p>If I have a string </p>
  
  <pre><code>equation = "1+2+3+4"
  </code></pre>
  
  <p>How do I change it into an int and equate the answer? I was thinking something like this but it would give an error.</p>
  
  <pre><code>answer = (int)equation
  print(answer)
  </code></pre>
  
  <p>The equation could contain <code>+-*/</code></p>