Code: SN
100 = 4*25
Formulae:
Number N is divisible by 25 iff least significant two digits are 00, 25, 50 or 75.
Example:
Number N = 59 60 05 44 76 75
is divisible by 25
Code: PU
P=100 (k=75=0 (mod 25) )
Formulae:
Number N is divisible by 25 iff least significant digit is divisible by 24
Example:
Number N = 98 76 54 32 00
is divisible by 25.
Code: CR
P=25 (k=1)
Formulae:
Number N is divisible by 25 iff least significant digit is 0
Example:
Conversion to base P=25 uses method, eg:
1) from decimal system P=10: P=10*1/2, next P^2 into 25
2) P=100*1/4
Number N = 68928 with base P=10
Conversion from P=100*1/4: digits in bracket [] multiply by 4
[6 89 | 28] = [24 | 356] 28 = [24 | 14*25+6] 25+3
[24] = 96 = 3*25+21
repair of digits, they are not bigger than 25:
96 356 28 = 3 (21+14) (6+1) 3 = 4 10 7 3
or
from P=10*1/2:
[6 8 9 2 | 8] = [12 16 18 4] 8
[1 3 7 8 | 4] = [2 6 14 16 ] 4
[2 7 5 | 6] = [4 14 10] 6
[5 5 | 0] = [10 10] 0
[1 1 | 0] = [2 2] 0
[2 | 2] = 4 2
number is 4 2 0 0 6 4 8 = 4201203 with base P=5
number is 4 20 12 03 = 4 10 7 3 with base 5^2 = 25
Number N isn't divisible by 25 because remainder is 3
