Ask HN: How can I “work-out” critical thinking skills as I age?

As I get older, I realized I’m not as sharp as I used to be. Maybe it’s from the fatigue of juggling 2 kids, but I’m very ill prepared for interviews because I simply can’t answer “product questions” and brain teasers. It’s a skill I need, and truthfully I was never good at consultant type questions to begin with but I’m seeing a lot of these questions in Data Science interviews.

Any help or resources will be tremendously appreciated.