The heuristic problem solver is used, at a very basic level, to solve crypto problems of certain types. A heuristic is a rule for a system in the form of an if then statement which is perfect for prolog. The rule is used to test the validity of a problem. So, we create a crypto problem with five numbers and a goal. The we test to see if any of the given heuristics applies to crypto problem we are testing. If it does then we apply the rule and display the fully parenthesized arithmetic equation. This output is the ‘then’ portion of the ‘if…then’ statement for each heuristic. When programming this, the ‘if’ is the given situation, such as the numbers and the goal that need to match the crypto. The ‘then’ is the action take when the ‘if’ portion is satisfied. If we cannot satisfy the ‘if’ then the problem, if possible, will be solved decompositionally.