Code: PU
P=100 (k=65=30 (mod 35) )
Formulae:
Number N is divisible by 35 iff 30*b+a = -5*b+a is divisible by 35
Example:
Number N = 98 76 54 32 15 = 28 6 19 32 15 =
-5( 28 6 19 32)+15 =
-5(-5( 28 6 19+32)+15 =
-5(-5(-5( 28 6+19)+32)+15 =
-5(-5(-5(-5*28+6)+19)+32)+15 =
-5(-5(-5* 6+19)+32)+15 =
-5(-5* 24+32)+15 =
-5* 17+15 = 0 (mod 35)
is divisible by 35.
Code: CR
P=70=7*10
Formulae:
Number N is divisible by 35 iff least significant digit is either 0 or 35
Example:
Number N = 8512160
[8 5 1 2 1 6 | 0] = [7 14 7 42 0 14 | 20] = 7*[1 2 1 6 0 2] 20
isn't divisible by 35
Properties of divisibility
11/16/17
number 34
Code: PU
P=100 (k=66=32 (mod 34) )
Formulae:
Number N is divisible by 34 iff 32*b+a = -2*b+a is divisible by 34
Example:
Number N = 98 76 54 32 10 = 30 8 20 32 10 =
-2( 30 8 20 32)+10 =
-2(-2( 30 8 20+32)+10 =
-2(-2(-2( 30 8+20)+32)+10 =
-2(-2(-2(-2*30+8)+20)+32)+10 =
-2(-2(-2* 16+20)+32)+10 =
-2(-2* 22+32)+10 =
-2* 22+10 = 0 (mod 34)
is divisible by 34.
P=100 (k=66=32 (mod 34) )
Formulae:
Number N is divisible by 34 iff 32*b+a = -2*b+a is divisible by 34
Example:
Number N = 98 76 54 32 10 = 30 8 20 32 10 =
-2( 30 8 20 32)+10 =
-2(-2( 30 8 20+32)+10 =
-2(-2(-2( 30 8+20)+32)+10 =
-2(-2(-2(-2*30+8)+20)+32)+10 =
-2(-2(-2* 16+20)+32)+10 =
-2(-2* 22+32)+10 =
-2* 22+10 = 0 (mod 34)
is divisible by 34.
Labels:
divisibility by 34
11/9/17
number 33
Code: PU
P=100 (k=67=1 (mod 33) )
Formulae:
Number N is divisible by 33 iff sum of digits is divisible by 33
Example:
Number N = 98 76 54 32 04 = 32 10 21 32 4 =
32+10+21+32+4 = 99 = 0 (mod 33)
is divisible by 33.
Code: SF 10*10-3*33=1
10(10b+a) = b+10a (mod 33)
Formulae:
Number N is divisible by 33 iff b+10a is divisible by 33
Example:
Number N = 68905
6890+10*5 = 6940
694+10*0 =694
69+10*4 = 109
10+10*9 = 100 = 3*33+1
isn't divisible by 33
Code: SF- 23*10-7*33=-1
23(10b+a) = -b+23a = -(b+10a) (mod 33)
It is the same as above.
P=100 (k=67=1 (mod 33) )
Formulae:
Number N is divisible by 33 iff sum of digits is divisible by 33
Example:
Number N = 98 76 54 32 04 = 32 10 21 32 4 =
32+10+21+32+4 = 99 = 0 (mod 33)
is divisible by 33.
Code: SF 10*10-3*33=1
10(10b+a) = b+10a (mod 33)
Formulae:
Number N is divisible by 33 iff b+10a is divisible by 33
Example:
Number N = 68905
6890+10*5 = 6940
694+10*0 =694
69+10*4 = 109
10+10*9 = 100 = 3*33+1
isn't divisible by 33
Code: SF- 23*10-7*33=-1
23(10b+a) = -b+23a = -(b+10a) (mod 33)
It is the same as above.
Labels:
divisibility by 33
number 32
Code: PS P=100.000
b100000+a = 32*3125b+a = a
Formulae:
Number N is divisible by 32 iff least significant digit a is divisible by 32
Example:
Number N = 98476 51430 98756
98756 = 4*24689
Number N isn't divisible by 32
Code: PU
P=100 (k=68=4 (mod 32) )
Formulae:
Number N is divisible by 32 iff 4*b+a is divisible by 32
Example:
Number N = 98 76 54 32 00 = 2 12 22 0 0 =
4(2 12 22 0)+0 =
4(4(2 12 22+0)+0 =
4(4(4( 2 12+22)+0)+0 =
4(4(4(4* 2+12)+22)+0)+0 =
4(4(4* 20+22)+0)+0 =
4(4* 6+0)+0 =
4* 24+0 = 0 (mod 32)
is divisible by 32.
Code: CR
P=800 (k=100*8)
Formulae:
Number N is divisible by 32 iff remainder from division by 800 is divisible by 32
Example:
Number N = 84 56 21 34
Conversion to P=100*8
[84, 56, 21 | 34] = [80, 456, 16] | 534 = 8*[10, 57, 2] | 534
The number N has least significant digit 534 = 2*267, so N isn't divisible by 32
b100000+a = 32*3125b+a = a
Formulae:
Number N is divisible by 32 iff least significant digit a is divisible by 32
Example:
Number N = 98476 51430 98756
98756 = 4*24689
Number N isn't divisible by 32
Code: PU
P=100 (k=68=4 (mod 32) )
Formulae:
Number N is divisible by 32 iff 4*b+a is divisible by 32
Example:
Number N = 98 76 54 32 00 = 2 12 22 0 0 =
4(2 12 22 0)+0 =
4(4(2 12 22+0)+0 =
4(4(4( 2 12+22)+0)+0 =
4(4(4(4* 2+12)+22)+0)+0 =
4(4(4* 20+22)+0)+0 =
4(4* 6+0)+0 =
4* 24+0 = 0 (mod 32)
is divisible by 32.
Code: CR
P=800 (k=100*8)
Formulae:
Number N is divisible by 32 iff remainder from division by 800 is divisible by 32
Example:
Number N = 84 56 21 34
Conversion to P=100*8
[84, 56, 21 | 34] = [80, 456, 16] | 534 = 8*[10, 57, 2] | 534
The number N has least significant digit 534 = 2*267, so N isn't divisible by 32
Labels:
divisibility by 32
10/31/17
number 31
Code: PU
P=100 (k=69=7 (mod 31) )
Formulae:
Number N is divisible by 31 iff 7*b+a is divisible by 31
Example:
Number N = 98 76 54 32 08 = 5 14 23 1 8 =
7( 5 14 23 1)+8 =
7(7(5 14 23+1)+8 =
7(7(7( 5 14+23)+1)+8 =
7(7(7(7* 5+14)+23)+1)+8 =
7(7(7* 18+23)+1)+8 =
7(7* 25+1)+8 =
7* 21+8 = 0 (mod 31)
is divisible by 31.
Code: SF 28*10-9*31=1
28(10b+a) = b+28a = b-3a (mod 31)
Formulae:
Number N is divisible by 31 iff b-3a is divisible by 31
Example:
Number N = 68931
6893-3*1 = 6890
689-3*0 =689
68-3*9 = 41
4-3*1 = 1
isn't divisible by 31
Code: SF- 3*10-1*31=-1
3(10b+a) = -b+3a = -(b-3a) (mod 31)
It is the same as above.
P=100 (k=69=7 (mod 31) )
Formulae:
Number N is divisible by 31 iff 7*b+a is divisible by 31
Example:
Number N = 98 76 54 32 08 = 5 14 23 1 8 =
7( 5 14 23 1)+8 =
7(7(5 14 23+1)+8 =
7(7(7( 5 14+23)+1)+8 =
7(7(7(7* 5+14)+23)+1)+8 =
7(7(7* 18+23)+1)+8 =
7(7* 25+1)+8 =
7* 21+8 = 0 (mod 31)
is divisible by 31.
Code: SF 28*10-9*31=1
28(10b+a) = b+28a = b-3a (mod 31)
Formulae:
Number N is divisible by 31 iff b-3a is divisible by 31
Example:
Number N = 68931
6893-3*1 = 6890
689-3*0 =689
68-3*9 = 41
4-3*1 = 1
isn't divisible by 31
Code: SF- 3*10-1*31=-1
3(10b+a) = -b+3a = -(b-3a) (mod 31)
It is the same as above.
Labels:
divisibility by 31
number 30
Code: CR
P = 3*10
Formulae:
Number N is divisible by 30 iff least significant digit is 0
Example:
Convert decimal number N = 8512160 into base P = 3*10=30, first step is enough
[8 5 1 2 1 6 | 0] = [6 24 9 21 9 24 | 20] = 3*[2 8 3 7 3 8] 20
Number N isn't divisible by 30
Code: PU
P=100 (k=70=10 (mod 30) )
This case method doesn't work - the formulae wishes to check a number N:
Number N is divisible by 30 iff N = 10*b+a is divisible by 30
P = 3*10
Formulae:
Number N is divisible by 30 iff least significant digit is 0
Example:
Convert decimal number N = 8512160 into base P = 3*10=30, first step is enough
[8 5 1 2 1 6 | 0] = [6 24 9 21 9 24 | 20] = 3*[2 8 3 7 3 8] 20
Number N isn't divisible by 30
Code: PU
P=100 (k=70=10 (mod 30) )
This case method doesn't work - the formulae wishes to check a number N:
Number N is divisible by 30 iff N = 10*b+a is divisible by 30
Labels:
divisibility by 30
10/23/17
number 29
Code: PU
P=100 (k=71=13 (mod 29) )
Formulae:
Number N is divisible by 29 iff 13*b+a is divisible by 29
Example:
Number N = 98 76 54 32 13 = 11 18 25 3 13 =
13( 11 18 25 3)+13 =
13(13(11 18 25+3)+13 =
13(13(13(11 18+25)+3)+13 =
13(13(13(11*17+18)+25)+3)+13 =
13(13(13* 2+25)+3)+13 =
13(13* 22+3)+13 =
13* 28+13 = 0 (mod 29)
is divisible by 29.
Code: SF 3*10-1*29=1
3(10b+a) = b+3a (mod 29)
Formulae:
Number N is divisible by 29 iff b+3a is divisible by 29
Example:
Number N = 68931
6893+3*1 = 6896
689+3*6 = 707
70+3*7 = 91
9+3*1 = 12
isn't divisible by 29
Code: SF- 26*10-9*29=-1
26(10b+a) = -b+26a = -(b+3a) (mod 29)
It is the same as above.
P=100 (k=71=13 (mod 29) )
Formulae:
Number N is divisible by 29 iff 13*b+a is divisible by 29
Example:
Number N = 98 76 54 32 13 = 11 18 25 3 13 =
13( 11 18 25 3)+13 =
13(13(11 18 25+3)+13 =
13(13(13(11 18+25)+3)+13 =
13(13(13(11*17+18)+25)+3)+13 =
13(13(13* 2+25)+3)+13 =
13(13* 22+3)+13 =
13* 28+13 = 0 (mod 29)
is divisible by 29.
Code: SF 3*10-1*29=1
3(10b+a) = b+3a (mod 29)
Formulae:
Number N is divisible by 29 iff b+3a is divisible by 29
Example:
Number N = 68931
6893+3*1 = 6896
689+3*6 = 707
70+3*7 = 91
9+3*1 = 12
isn't divisible by 29
Code: SF- 26*10-9*29=-1
26(10b+a) = -b+26a = -(b+3a) (mod 29)
It is the same as above.
Labels:
divisibility by 29
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