title: How to design an algorithm to calculate countdown style maths number puzzle
body: <p>I have always wanted to do this but every time I start thinking about the problem it blows my mind because of its exponential nature.</p>
  
  <p>The problem solver I want to be able to understand and code is for the countdown maths problem:</p>
  
  <p>Given set of number X1 to X5 calculate how they can be combined using mathematical operations to make Y.
  You can apply multiplication, division, addition and subtraction.</p>
  
  <p>So how does <code>1,3,7,6,8,3</code> make <code>348</code>?</p>
  
  <p>Answer: <code>(((8 * 7) + 3) -1) *6 = 348</code>.</p>
  
  <p>How to write an algorithm that can solve this problem? Where do you begin when trying to solve a problem like this? What important considerations do you have to think about when designing such an algorithm?</p>