### Bookshelf

Total GMAT MathJeff's complete Quant guide, on sale now! |

Total GMAT VerbalEverything you need to ace GMAT Verbal! |

**1,800 Practice Math Questions**

Buy Jeff's books at Amazon.com

GMAT Official Guide, with IR

OG Math | OG Verbal

OG12 & Quant Rev solutions!

**GMAT Question of the Day**

Beginner's Guide to the GMAT

GMAT Hacks Affiliate Program

### Categories

- General Study Tips
- Goals and Planning
- CAT Strategy
- The Mental Game
- GMAT Math Strategy
- GMAT Math Topics
- Mental Math
- Data Sufficiency
- Critical Reasoning
- Reading Comprehension
- Sentence Correction
- Analytical Writing Assessment
- Integrated Reasoning
- IR Explained
- Business School Admissions
- GMAT Prep Resources
- Practice Questions
- Total GMAT Math
- Total GMAT Verbal
- GMAT 111

## Video: Mental Math: Percents

###### July 29, 2010

You should follow me on Twitter. While you're at it, take a moment to
subscribe to
GMAT Hacks via RSS or Email. |

Today's video covers one of my favorite mental math tricks: calculating percents by starting with 10%, 5%, and 1%. It's powerful, and it's a great way to get you thinking more abstractly about all sorts of calculations--not just percents.

Some of the subjects covered in the video overlap with something I wrote several years ago. So if you prefer the text version, or you'd like to have it handy for review after watching, click here.

**About the author:** *Jeff Sackmann has written many
GMAT preparation books, including the popular Total GMAT Math,
Total GMAT Verbal, and GMAT 111. He has also created
explanations for problems in The Official Guide, as well as
1,800 practice GMAT math questions.*

Total GMAT Math
The comprehensive guide to the GMAT Quant section. It's "far and away the best study material
available," including over 300 realistic practice questions and more than 500 exercises! |