Beefaco Rampage and Maths share common ancestory... the main advantage of Maths over the Rampage apart from being less cluttered and therefore more ergonomic (which is a very good thing in itself - & don't get me started on the frap tools falistri, for this very reason) though is that there's a lot more documentation available - not only are there a myriad of videos (some of which are very good), but there's also the 'Maths Illustrated Supplement', which has 32 example patches for Maths - great as a basic guide to getting more out of Maths, but even better if you spend the time thinking about the what, why and how of what it's doing and use that as part of building up a modular patching mindset...
As for a mixer... I really like the Tesseract Tex-Mix - it's not perfect, but it's inexpensive and expandable - doesn't have 1/4" outputs (except for the headphone out), but as far as I know very few modular mixers do... if you must have 1/4" outputs, then the befaco output module is decently priced... & if you can wield a soldering iron, both of these are available as DIY kits...
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities