title: "TypeError: cannot concatenate 'str' and 'int' objects" when trying to use printf-style formatting
body: <p>I don't see problem in here, but Python thinks different:</p>
  <pre><code>x = 3
  y = 7
  z = 2
  
  print &quot;I told to the Python, that the first variable is %d!&quot; % x
  print &quot;Anyway, 2nd and 3rd variables sum is %d. :)&quot; % y + z
  </code></pre>
  <p>I get <code>TypeError: cannot concatenate 'str' and 'int' objects</code>.</p>
  <p>Why is that so? I haven't setted any variable as string... as much as I see.</p>