No worries! It sort of depends on how much maths you know really. All the books and pretty much all first year first semester maths for Econ classes basically do a bit of revision from a-level maths but frame it in an economic context.
So they all might start from the basics of algebra, simultaneous equation and quadratic functions. Then they'll go onto univariate differentiation, stationary points/max and mins, integration, multivariate calculus, matrix algebra, differential equations and then dynamic systems. There will also be some further topics in each book. So most start in a pretty basic manner and then get progressively harder.
The differences I would say is that the Hoy and Simon & Bloom books are a bit more proof-based so perhaps harder if you're not used to that. Personally I like Alpha Chiang's book as it's well written and very portable (book rather than textbook dimensions) although it's older than the rest. If you wanna work through things slowly and start from the basics then I'd go with Essential Mathematics for Economic Analysis by Sydsaeter et al.
Btw you should definitely buy them off eBay or something than new. For example, when I bought Alpha Chiang's book it was like £40-50 new on the publisher's website but £2.50 on eBay. Also I wouldn't recommend getting the latest editions of these books, just get the cheapest you can get really as they don't change much