Digital Root
Description
By Eddie Shore, January 2016 (Eddie's Math and Calculator Blog)
Define DR(n) as the digital root function:
DR(n) = n – 9 * int((n-1)/9), n > 0
DR returns the sum of n’s digits and repeats until a single digit remains.
Enter integer n and press f A. DR(n) is displayed.
Examples:
DR(4514) = 5
DR(9376) = 7
DR(636088) = 4
DR(761997) = 3
Program Resources
Labels
Name |
Description |
|
A |
Digital Root |
|
Program
Line |
Display |
Key Sequence |
|
000 |
|
|
|
001 |
42,21,11 |
f LBL A |
|
002 |
36 |
ENTER |
|
003 |
36 |
ENTER |
|
004 |
1 |
1 |
|
005 |
30 |
− |
|
006 |
9 |
9 |
|
007 |
10 |
÷ |
|
008 |
43 44 |
g INT |
|
009 |
9 |
9 |
|
010 |
20 |
× |
|
011 |
30 |
− |
|
012 |
43 32 |
g RTN |
|