You've clearly done your homework, but the way you've framed this will make your prep harder than it needs to be. You're trying to decide which resource is "enough" for the basics and build everything else around it. With rusty fundamentals and a seven-year gap, the patchwork itself is the problem. Different resources teach the same content differently, cover slightly different things, and sequence topics differently, so blending them leaves gaps exactly where a rusty student can least afford them. What you want instead is one comprehensive, structured, sequenced system that covers every topic and confirms you've mastered each one before you move on.
The method inside that system matters just as much. Work one topic at a time: learn the concepts, formulas, logic, and techniques, and expect some of it to feel genuinely new rather than simply forgotten. Practice only that topic, untimed at first, until your accuracy is consistently high. On every miss, diagnose the cause: concept gap, misread, careless error, or trap answer. A few days later, redo the missed questions from scratch without looking at the solution. If you can't solve it cold, it isn't solid yet. Only then add timing, and only after that mix the topic into broader sets.
The GMAT Club hard-question sets you mentioned are genuinely valuable and you'll want them. At the same time, hard questions pay off most after the foundation is built, so save them for the mixed-practice stage. The Official Guide is the same: excellent, realistic practice once the topical work has given you something to apply it to. And material built for a different exam usually isn't efficient, since it emphasizes content the GMAT doesn't test. Keep your prep GMAT-specific.
For the course itself, look for a sequenced, topic-by-topic curriculum, comprehensive coverage across Quant, Verbal, and Data Insights, practice organized by topic and difficulty, high-quality questions with written and video explanations, strong analytics, real tools for error analysis and review, mastery-based progression, and serious treatment of Data Insights. The best courses now include AI coaching done well, where you upload your work and get feedback on where your reasoning broke down. Check reviews on GMAT Club, Beat the GMAT, and Trustpilot, and take a trial before you commit.
So rather than picking which book anchors a patchwork, put one structured course at the center and work through it topic by topic to mastery, adding timing, then mixed sets, and bringing in the GMAT Club hard sets and Official Guide at that later stage.
This article goes deeper:
20 Tips for Increasing Your GMAT Quant Score.
peazyy
Hi, I'm really confused about the best way to approach GMAT Quant. It's been around 7 years since I studied maths, so my fundamentals are pretty rusty.
From what I've seen and read, GMAT Ninja is great for understanding concepts, and GMAT Club's hard questions seem to be the go-to for practice.
Personally, I was thinking about using Manhattan All the Quant + DI to rebuild my basics and then move on to the Official Guide.
But the question is: is Manhattan enough to build a solid foundation, or should I be using something else for the basics? I've even considered Arun Sharma (CAT Quant), but I'm not sure if that's unnecessary for the GMAT.
Would really like to hear what worked for people who started with a weak Quant background.