Hi,
Quant is much easier to improve than is Verbal. Just learn the concepts (through some Math guide books), practice quant problems in
OG 12 (it's a must), and familiarize yourself with real quant questions through GPrep test.
If you are rusty with quant,
MGMAT Math books are very good to brush up quant knowledge. I only used
MGMAT Word translation and Number Properties and found these books very helpful. Another valuable quant resources are GMAT Club dianogstic test and GMAT Club math book. The GMAT Club Diagnostic test is not representative of GMAT, but is a great material to learn the concepts. GMAT Club Math book is neatly written and cover almost all topics in quant, it's well worth reading!
After equipping yourself with quant knowledge, move on to OG12. Make sure you understand the concepts tested in each problem and the take-aways to apply to other problems. Do not rush! Reviewing every incorrect answer is a must. Keep an
error log or make flashcards for incorrect answers. Doing tons of problems w/o spending time on reviewing doesn't get you to anywhere, actually.
The final step is to take GPrep tests. I personally learn a lot from the incorrect answers from GPrep tests, which give me a sense of how real GMAT problems are and learn some tricks. Googling the incorrect answers often links to
MGMAT forum. Studying from
MGMAT Instructors' explanations is extremely helpful.
just a reminder: just book the test when you are well-prepared and confident.
my 2 cents
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