13	  4	
	---   *  --- =
	 5	  7

	There's just no way to reduce this problem.
	When we multiply 13/5 * 4/7 we get 52/35.

	 34	 45
	---  *  ---- =
	 25	 17

	Here we can reduce with the 45 and the 25.
	Since both are divisible by 5 we can change the problem
	like this:

	 34	 9	
	---  *  --- =
	 5	 17

	We can also reduce with the 34 and the 17 like this:

	 2	 9
	---  *  --- =
	 5	 1

	ANSWER: 18/5.