There are top pros who claim to have very little math knowledge. Whether or not they are telling the truth is another thing. You certainly don't need a degree in math to be a winning player.
That said, you need some math to be good and more math usually correlates to more knowledge which, in general, makes you better player.
Firstly, you should be able to link your number of outs to your % chance to catch one of those outs in all post-flop situations.
You should have at least some sense of villains' ranges and betting habits, which (nowadays) means using a HUD to do the math and then using reason and intuition for the rest.
You should definitely be able to work out pot odds, implied odds, SPR (stack to pot ratio), and ESS (effective stack size) on-the-fly at the table.
You will quickly memorize all of these simple, often repeated, useful bits of information. The same (or at least quite similar) things happen over and over again, which makes it go pretty quickly. Once these maths become instant knowledge instead of you working them out, you will start to find more maths that you can think about. That's the path to improvement, IMO.
EDIT: As far as what you should be studying: yourself. Go over your HH. Spend at least as much time reflecting on your play as you do actually playing. In every other sport, practice outweighs competition. That same mentality needs to be applied to poker.