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

Redeem

Multplication of n consecutive numbers.

Expert replies
Source: — Problem Solving |

by Anurag@Gurome » Sun Mar 18, 2012 10:15 pm
puneetluthra198508 wrote:what's the best way to calculate the solution for multiplication of first n numbers..
ex ... p(100) -> 1*2*3*4___99*100..
Product of first n numbers is 1 * 2 * 3 * ... * n = n! as n! = n * (n - 1) * ... 3 * 2 * 1

In this case, 1 * 2 * 3 * 4 ... 99 * 100 = 100!
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Join the discussion

by Whitney Garner » Fri Mar 23, 2012 1:43 pm
puneetluthra198508 wrote:what's the best way to calculate the solution for multiplication of first n numbers..
ex ... p(100) -> 1*2*3*4___99*100..
Hi puneetluthra198508!

Anurag@Gurome is exactly right in that you're actually looking at 100!. But to make sure it is clear for your question, there is NO way to calculate this actual value without a heavy duty calculator. You will never be asked to do so on the test as the number has 157 significant digits (it equals approximately 9.3 x 10^157.

The test might ask you how many trailing 0s it has (the number of zeros between the decimal and the first non-zero digit - ie, the number 97000 has 3 trailing 0s).

I'll let you puzzle over how to figure that one out and you can yell back for help if you get stuck!

Hope this helps!
:)
Whit
Whitney Garner
GMAT/GRE/EA Instructor & Anxiety/Accommodations Coach
www.whitneygarner.com

Contributor to Beat The GMAT!

Math is a lot like love - a simple idea that can easily get complicated :heart-eyes:
Join the discussion