I always thought I was an intelligent person until I found myself:
Easily distracted by external things
Relying too much on my notes and not remembering things
Relying too much on my device to make calculations
For this reasons, I started to train my brain as much as I train my body, with the help of some useful apps:
Neuronation, will design a custom journey based on your lacks and will make you do interesting games and exercises to improve the capabilities of your brain
Kinnu, you will have most of the human knowledge tailored in different "learning paths " you can follow as you like. If you like learning like me it's one of the best apps in the market
Chess, nothing is more engaging than a game of chess, I like to use chess as a way to spend some time relaxing while doing something that keeps my brain active (instead of doom scrolling)