GMAT Math

Hi guys!
I recently purchased a copy of Manhattan GMAT advanced quant.Since I am pressed
for time,I was wondering if I should focus on some of the chapters more and
skim through the rest and jump right into the Problem sets?

What are the more important chapters in the book?

Also does anyone have a concept wise classification of the problem set questions?
I would like to do the problem topic wise...

Thanks a ton guys!

Some areas to focus on:

Factors and Multiples
Fractions
Exponents and roots
Statistics
Linear equations
systems of equations
Inequalities
Percents
Ratios


This is about half of the exam.