title: How to split up a two-digit number in C
body: <p>Let's say I have a number like 21 and I want to split it up so that I get the numbers 2 and 1.</p>
  
  <p>To get 1, I could do 1 mod 10. So basically, the last digit can be found out by using mod 10.</p>
  
  <p>To get 2, I could do (21 - (1 mod 10))/10. </p>
  
  <p>The above techniques will work with any 2-digit number.</p>
  
  <p>However, let me add a further constraint, that mod can only be used with powers of 2. Then the above method can't be used.</p>
  
  <p>What can be done then?</p>