I am the creator of TutoriaLibre (tutorialibre.com) and Agilitas (agilitas.app), two completely free websites where you can study and practice programming, math, memorization and much more.
While many courses and trainings today focus on video lessons, I found that written materials and interactive challenges can sometimes be much more helpful, and that is what led me to create such sites.
Both sites are completely free and require no registration, so you can come and go with no commitments, and proceed at your own pace.
Supporting me will help keep these projects alive and always free for everyone.