title: Iterate over digits of integers inside of array
body: <p>I have this code below:</p>
  
  <pre><code> a = [435,276,434]
  
   def product(a)
     final = 1
     for e in a
       for p in a[e]
         final*=p
       end
     end
     final
   end
  
   puts product(a)
  </code></pre>
  
  <p>I'm wondering how I can iterate over this array twice where the result is 4*3*5 = 60, 2*7*6 = 85, and 4*3*4 = 48</p>
  
  <p>I wrote some code up above which I thought would do the trick here but Ruby keeps on returning an error.</p>