just
basic algebra. Being able to juggle math in your head is great plus for your General nav exam and others. Basic trig knowledge is also a plus.
Physics, what goes up must come down. Newtons law but then it's taught in my ATPL ground school. Bernioulli's law as well.
Basic magnetism is also taught there.
If you wish to get a good start then I suggest getting a good book on weather, one that explains everything in colours and graphs.
Mass and balance, performance, pof and Gnav are probably the most math extensive.
The suggestion my ATPL teacher gave me before we started ATPL ground school, START JUGGLING MATH in your head. I regret not having done so.
When I say juggle math in your head it doesn't mean you should be able to get the square root of 10203050. It means you should be able to add up numbers like 37, 48, 56 together quickly as well as subracting them from each other quickly.
A good pilot dictionary to explain some the POF jargon.