Hi,
I started to study math again after a long while, and as I was so rusty, I had to go back into stuff from before highschool math, currently reviewing prime numbers, but I came to a point that I changed subjects (operations with rational numbers) and the exercises that will come daily won't comprehend what I've learned before, and that's an easy way of forgetting it again, so I was wondering, is there anything similar to anki for studying math, like, with exercises on specific subjects that you could recommend? Thanks!