Below are video explanations to all of the math (Problem Solving and Data Sufficiency) practice questions in the GMAT Official Guide, 12th Edition.
You can purchase the book on Amazon.
You should also consider using Magoosh GMAT Prep. Our comprehensive online prep program features over 250 video lessons and 800 online practice questions with video explanations to help you conquer the GMAT.
Click here to learn more.