Go on eBay and buy the following Open University book sets. They go for around £30-50 a pop: MU123 (basics), MST124 (more complex). 6 months worth of study in each book set. If you like it do MST125 (even more complex) and M140 (stats) after. That's the first year of a mathematics degree literally from the ground up through GCSE and A-level stuff. If you really like it, get a student loan and do the associated accredited degree.
£30 for 6 months is pretty damn cheap and you get to keep it forever!
This is a proper accredited course developed over 50 years or so with its own textbooks and material from a respectable university, not a gamified subscription portal experiment put together by god knows who that can disappear in a puff of smoke at no notice.
£30 for 6 months is pretty damn cheap and you get to keep it forever!
ebay example of the latest edition for sale: https://www.ebay.co.uk/itm/197011707080
On archive.org too if you are happy with PDFs: https://archive.org/search?query=creator%3A%22The+MU123+Cour...
First MU123 book A: https://archive.org/details/BookAMU1232ndedOU2014/MU123-Book...
This is a proper accredited course developed over 50 years or so with its own textbooks and material from a respectable university, not a gamified subscription portal experiment put together by god knows who that can disappear in a puff of smoke at no notice.