Hi MariaMia,
I’m glad you reached out, and I’m happy to help. Although you may find that you need more than just one month to improve your quant skills, here is some advice you can follow in order to do so. First off, since you scored 370 on your GMAT (with a presumably low quant score), it’s clear that you need to follow a study plan that allows you to learn GMAT quant from the ground up. In other words, follow a study plan that allows you to learn each GMAT quant topic individually and the practice each topic until you’ve gained mastery. Let me expand on this idea further.
For example, if you are learning about Number Properties, you should develop as much conceptual knowledge about Number Properties as possible. In other words, your goal will be to completely understand properties of factorials, perfect squares, quadratic patterns, LCM, GCF, units digit patterns, divisibility, and remainders, to name a few concepts. After carefully reviewing the conceptual underpinnings of how to answer Number Properties questions, practice by answering 50 or more questions just from Number Properties. When you do dozens of questions of the same type one after the other, you learn just what it takes to get questions of that type correct consistently. If you aren't getting close to 90 percent of questions of a certain type correct, go back and seek to better understand how that type of question works, and then do more questions of that type until you get to around at least 90 percent accuracy in your training. If you get 100 percent of some sets correct, even better. Number Properties is just one example; follow this process for all quant topics.
When you are working on learning to answer questions of a particular type, start off taking your time, and then seek to speed up as you get more comfortable answering questions of that type. As you do such practice, do a thorough analysis of each question that you don't get right. If you got a remainder question wrong, ask yourself why. Did you make a careless mistake? Did you not properly apply the remainder formula? Was there a concept you did not understand in the question? By carefully analyzing your mistakes, you will be able to efficiently fix your weaknesses and in turn improve your GMAT quant skills.
So, work on accuracy and generally finding correct answers, work on specific weaker areas one by one to make them strong areas, and when you take a practice GMAT or the real thing, take all the time per question available to do your absolute best to get right answers consistently. The GMAT is essentially a game of seeing how many right answers you can get in the time allotted. Approach the test with that conception in mind, and focus intently on the question in front of you with one goal in mind: getting a CORRECT answer.
You also may find it helpful to read this article about
How To Increase Your GMAT Quant Score.
Feel free to reach out with further questions.
Good luck!