I think this is very correct for studying, when I was in undergrad, if I saw the answer, I found it was more effective to skip past it and solve it later. Even more important, once I am done, I should not go look at the answer to confirm if I am right or wrong, I should try and validate the answer by looking at my solution and trying to figure out if my solution is correct or not because there are plenty of ways to "disqualify" an answer, once I learned to do this well, my grades really went up.

However, I don't always agree with the fact that we don't have the answer in front of us in many situations. There are a lot of situations beyond grade school and undergrad where you do have the answer in front of you. Sometimes it's in for form of Numpy or Matlab or Simulink. It might be someone's research publication. Replicating these by working both forwards and backwards from their libraries or results can be much more effective.