© 1999 T
EXAS
I
NSTRUMENTS
I
NCORPORATED
TI
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34
Û
: A Guide for Teachers
83
Combination (nCr)
H
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
A
B
C
D
AB and BA
count as only 1
combination.
AB AC AD
BA BC BD
CA CB CD
DA DB DC
Press Display
4
H
"
nPr nCr !
¹
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2
<
4 nCr 2
º
6.