Also, manual calculation is fundamentally how you learn mathematics. Following along is a first step, but is not good enough to learn the material. You need to do the calculations and run into problems, so you can re-create the knowledge in your brain.
EDIT> Take Coursera's Learning How to Learn Course. It sounds flaky, but will accelerate all of your other learning, and help with procrastination as well.
You really only need to know arithmetic to get started.
Use Anki to create flash-cards so that you learn faster and don't forget.
https://apps.ankiweb.net/
Also, manual calculation is fundamentally how you learn mathematics. Following along is a first step, but is not good enough to learn the material. You need to do the calculations and run into problems, so you can re-create the knowledge in your brain.
EDIT> Take Coursera's Learning How to Learn Course. It sounds flaky, but will accelerate all of your other learning, and help with procrastination as well.
https://www.coursera.org/learn/learning-how-to-learn