Factorials Flashcards
1
Q
What is a factorial?
A
n! = n * (n - 1) (n - 2) … 1
2
Q
so 4! = ?
A
4! = 4 * 3 * 2 * 1 4! = 24
3
Q
what is 3! = ?
A
3! = 3 * 2 * 1 3! = 6
4
Q
what is 2!
A
2! = 2 * 1 2! = 2
5
Q
what is 1!
A
1! = 1
6
Q
what is 0!
A
0! = 1
7
Q
How could you rewrite 5! ?
A
you could say 5! = 5 * 4!
8
Q
What is another way you could re write 5! ?
A
5! = 20 * 3!
9
Q
What is 7! / 6!
A
7 * 6! / 6!
which = 7
10
Q
What is true about factorials greater than 4 ?
A
Any factorial greater than 4! has a units digit of 0
11
Q
what is 1! ?
A
1
12
Q
What are good ways to solve hard factorial problems?
A
Cancel and factor
13
Q
How could you simplify 8! - 7! ?
A
You can factor so
8 * 7! - 7! = 7! (8 - 1)
which = 7! * 7
14
Q
Can factorials be added or subtracted? Does 6! + 7! = 13! ?
A
Answer = no
15
Q
any factorial greater than 4 factorial has a units digit of what?
A
of 0
5! = 120
