Parentheses, Factorial, Random numbers – Texas Instruments Calculator User Manual
Page 14: Combinations, Permutations, Rounding

10
Overview of Calculator Operations
Parentheses
9 :
Use parentheses to control the order in which the calculator evaluates a
numeric expression in division, multiplication, powers, roots, and
logarithm calculations. The calculator includes up to 15 levels of
parentheses and up to 8 pending operations.
Note: You do not have to press
: for expressions ending in a series of
closed parentheses. Pressing
N closes parentheses automatically,
evaluates the expression, and displays the final result. To view
intermediate results, press
: once for each open parenthesis.
Factorial
& g
The number for which you compute a factorial must be a positive integer
less than or equal to 69.
Random Numbers
& a
The calculator generates a random real number between zero and one
(0<x<1) from a uniform distribution.
You can repeat a sequence of random numbers by storing a seed value in
the random number generator. Seed values help you recreate
experiments by generating the same series of random numbers.
To store a seed value, key in an integer greater than zero and press
D
& a.
Combinations
& s
The calculator computes the number of combinations of n items taken r
at a time. Both the
n
and
r
variables must be greater than or equal to 0.
Permutations
& m
The calculator computes the number of permutations of n items taken r
at a time. Both the
n
and
r
variables must be greater than or equal to 0.
Rounding
& o
The calculator computes using the rounded, displayed form of a number
instead of the internally stored value.
nCr
n
!
n r
)! r!
×
–
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nPr
n
!
n r
)!
–
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