© 1999
T
EXAS
I
NSTRUMENTS
I
NCORPORATED
TI-30X
Ù
S: A Guide For Teachers
71
Factorial (!)
H
Using the digits 1, 3, 7, and 9 only
one time each, how many 4-digit
numbers can you form?
4! = x
1
3
7 9
A
B
C
D
ABCD
BACD
CABD
DABC
ABDC
BADC
CADB
DACB
ACBD
BCAD
CBAD
DBAC
ACDB
BCDA
CBDA
DBCA
ADBC
BDCA
CDAB
DCAB
ADCB
BDAC
CDBA
DCBA
Press Display
4
H
"
"
nPr
nCr
!
¹
-
DEG
<
<
4!
'
24.
DEG