Summary: Many people hold the misconception that one is a prime number. This
mathematics poster explains it all.
One
is Not Prime
I usually
try to introduce the concept of 1 not being prime by examining the mathematical
definition closely.
'For
a number to be prime it must have TWO different
factors'.
In
1's case its factors are 1 and 1.
For
a number to be prime it must be able to be divided by itself AND 1.
In
the case of 1 'itself ' IS one.
NB This Prime Number Math Wall Poster has had a rather significant update since I first made it c. 2004. Click on the image above to grab the new poster.
