Hi S. -
For Math,
MGMAT puts out a book called “Advanced Quant” that is separate from their main book set. I think that and the
GMAT Club tests are the best sources for moving up to Q51. When you do
GMAT Club tests, I’d suggest looking at the solutions for the problem given in the comments, even for questions you get right. Sometimes different people will suggest different ways to do a problem, or ask for a clarification of something you didn’t even think of. You might be able to find a way to do the problem that makes more sense to you or would be faster for you than the way you did (correctly or not) solve it.
It seems like you’re already pretty strong in math, so I don’t know how much you’ll need to do this, but if you’re not already solid on your multiplication tables, perfect squares, perfect cubes, Pythagorean triples, etc., I’d suggest making flashcards with something like Anki.
https://apps.ankiweb.netA lot of GMAT math is about your ability to estimate and have good number sense/intuition. So knowing numbers and formulas like that down cold can help you get through much of the test faster, saving you time to spend a bit longer on the difficult questions.
For Verbal, I’m probably the wrong person to ask.
e-gmat seems to work well for a lot of people around here; I don’t know anything about it personally. When you’re first starting your studying, it can be helpful not to worry too much about timing. Sometimes as you’re learning the techniques that the books and prep courses recommend will make you slower instead of faster temporarily as you get familiar with the technique. But it can be very helpful to read, e.g, an article from The Atlantic or The New Yorker or an RC passage and trying to figure out the structure - outline it. What is the main idea in each paragraph? How does each sentence contribute to that idea or argument?
Just as a starting point, here’s a recent New Yorker article that seems like a kind of topic that might end up on the GMAT:
https://www.newyorker.com/books/page-tur ... mod-latest