BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

How to solve factorials - Shortcut?

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
GMAT Instructor
Posts: 1223
Joined: Thu May 01, 2008 3:29 pmFollowed by: 15 members
Location: Los Angeles, CA
Thanked: 185 times

by VP_Jim » Sun Sep 21, 2008 12:35 pm
You'd never have to calculate 30! (or anything even close to it) on the GMAT. It's good to know the factorials up to, say, 5!, though.

Remember: the vast majority of the time, the GMAT does NOT test your computational abilities. If you find yourself doing lots of math, you're probably doing something wrong.
Jim S. | GMAT Instructor | Veritas Prep
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 871
Joined: Wed Aug 13, 2008 7:48 am
Thanked: 48 times

by stop@800 » Sun Sep 21, 2008 1:07 pm
Where are you required to solve this factorial?

The question must be expecting you to extract something from this number like units place or no of zeros or something else that can be obtained without calculating the value.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 301
Joined: Tue Apr 22, 2008 6:07 am
Thanked: 2 times

by beater » Sun Sep 21, 2008 3:27 pm
I did not come across a question that required solving for 30!. But, I was just curious if there was a shortcut to solve factorials. Thanks!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Sun Apr 14, 2013 5:44 pm

by MediatorOfDeath » Sun Apr 14, 2013 5:49 pm
There is a shortcut to finding factorials. It lets you do about half of the work, and get the same answer. I just recently discovered it, and made a website to put it on. Here is the link. If you are looking for speed, I would use the first method I share, and not worry about the second. Enjoy! :)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Mon Apr 15, 2013 4:22 am
As VP_Jim mentioned, the GMAT will never require you to perform such a series of tedious calculations. However, when dealing with the combination formula, nCr = n!/(r!)(n-r!), you will have to work with several factorials. In these cases, there is a nice shortcut that will allow you to calculate combinations (like 12C3) in your head.

Here's our free video on this topic: https://www.gmatprepnow.com/module/gmat-counting?id=789

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1