Sharp EL-9900 - Manual (Page 58)

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Chapter 3: Basic Calculations — Basic Keyboard
6 nCr Returns the total number of combinations for selecting “r” item out
of “n” items.
n
C
r
=
n!
r!(n – r)!
Example
• How many different groups of
7 students can be formed with
15 students?
1 5 M C 6 7
E
7 ! Returns a factorial.
Example
• Calculate 6
Ч
5
Ч
4
Ч
3
Ч
2
Ч
1.
6 M C 7 E
D CONV
CONV sub-menu items are to be used when converting a number
in decimal form (degrees) to a number in sexagesimal form
(degrees, minutes, seconds), or vice versa.
The “base 60” sexagesimal system, as well as the minutes-
second measurement system, was invented by the Sumerians,
who lived in the Mesopotamia area around the fourth millennium
B.C.(!) The notion of a 360 degrees system to measure angles
was introduced to the world by Hipparchus (555-514 B.C.) and
Ptolemy (2nd cent. A.D.), about 5000 years later. We still use
these ancient systems today, and this calculator supports both
formats.
1 →deg Takes a number in sexagesimal form, and converts it into a
decimal number.
Example
• Convert 34° 56’ 78” to
degrees.
3 4 M E 1 5 6
M 2 7 8 M
3 M D 1
E
Sexagesimal
and Degree
System