It is called "factorial." For example, 4! is read "four factorial."
What it means is 4 x 3 x 2 x 1; that is, multiply the numbers starting with 4 and going down to 1.
As another example, 7! = 7x 6 x 5 x 4 x 3 x 2 x 1 = 5040.
Factorials only make sense when they are applied to nonnegative integers.
Also, 1! = 1, and 0! = 1 as well. This is to make patterns in the factorials make sense; in particular, n! measures the number of ways you can arrange n objects in a line. There is 1 way to do this with 1 or 0 objects
It is called "factorial." For example, 4! is read "four factorial."
What it means is 4 x 3 x 2 x 1; that is, multiply the numbers starting with 4 and going down to 1.
As another example, 7! = 7x 6 x 5 x 4 x 3 x 2 x 1 = 5040.
Factorials only make sense when they are applied to nonnegative integers.
Also, 1! = 1, and 0! = 1 as well. This is to make patterns in the factorials make sense; in particular, n! measures the number of ways you can arrange n objects in a line. There is 1 way to do this with 1 or 0 objects
