User manual

© 1999 T
EXAS
I
NSTRUMENTS
I
NCORPORATED
TI-30X ÙS: A Guide for Teachers
69
You have space for 2 books on your
bookshelf. You have 4 books to put
on the shelf. Use this formula to
find how many ways you could place
the 4 books in the 2 spaces.
4 nCr 2 = x
 
ABCD
H
AB and BA
count as only
1 combination.
AB AC AD
BA
BC BD
CA
CB CD
DA
DB DC
Press Display
4 H "
nPrnPr nCrnCr ! !
&
------
DEG
2 <
4 nCr 24 nCr 2
'
6.6.
DEG
Combination (nCr)