title: Ceil and floor equivalent in Python 3 without Math module?
body: <p>I need to ceil and floor 3/2 result (1.5) without using <code>import math</code>.</p>
  
  <p><code>math.floor(3/2)</code> => <code>3//2</code>
  <code>math.ceil(3/2)</code> => ?</p>
  
  <p>OK, here is the problem:
  to sum all numbers
  15 + 45 + 15 + 45 + 15 ...
  with N items.</p>
  
  <p><code>sum = (n//2) * 5 + int(n/2) * 15</code></p>