Great Practice in Addition to the Official Guide

After completing the Official Guide quant questions, I realized that it lacked 700+ questions. I read on many testimonies of past test takers achieving high score that they extensively practiced using the gmatclub tests. I then decided to purchase the gmatclub tests and found the questions and Bunuel's explanations extremely helpful. I would recommend them to anyone aiming for a high score in quant. The practice mode is also interesting to use since you can spend some time to understand each explanation after a question.
I would also highly recommend the gmatclub math book in addition to these tests which helped me a lot to understand how to approach certain types of questions