You may also like

problem icon

Forgotten Number

I have forgotten the number of the combination of the lock on my briefcase. I did have a method for remembering it...

problem icon

Powerful Factorial

6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest power of two that divides exactly into 100!?

problem icon

Trailing Zeros

How many zeros does 50! have at the end?

Factoring Factorials

Age 11 to 14 Challenge Level:

Find the highest power of 11 that will divide 1000! exactly.

[Factorial 1000, written 1000!, is the product of the first 1000 whole numbers 1 x 2 x 3 x ... x 1000]

The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
Copyright © 1997 - 2019. University of Cambridge. All rights reserved.
NRICH is part of the family of activities in the Millennium Mathematics Project.