Its not? There just arent big enough test cases to see a difference. Try triangular 100000000 `shouldBe` 5000000050000000 for example.

| b = x would be fine. Straight pattern matching is another possibility, but it's mostly a matter of taste.

I wouldn't worry too much about any difference between case, if and | expressions and pattern matches. After desugaring, there's probably no appreciable difference anyway. I would be not at all surprised if most solutions generate exactly the same bytecode in the end.

That being said, learn the syntax first, how to interpret the error messages as best you can - write clean code later, you can always refactor.

Haskell is about expressions, guards are just IF blocks, in general

boolValue = True
if boolValue == True then "It is true" else "It is false"

would normally just be

boolValue = True
if boolValue then "It is true" else "It is false"

Thanks for the feedback! I was using Codewars to help learn Haskell so I'm not surprised my solution isn't great. Is | b = x valid or do you have another suggestion. Thanks again.

b == True is an antipattern.