Yes, yes, and no. 3- sum of digits must be multiple of 3. 6- sum of digits must be multiple of 3 and number must be even (multiple of 2). 9- sum of digits must be multiple of 9. (The sum of the digits here is 21.)
A number is divisible by 3 if the sum of its digits is a multiple of 3. A number is divisible by 6 if the sum of its digits is a multiple of 3 and it's even. A number is divisible by 9 if the sum of its digits is a multiple of 9.
420
No factor of 9 has three digits. 450 is a three-digit multiple of 150 (and of 9) with a digit sum of 9.
Start with the smallest multiple of 13 and continue with the next smallest until finding one that fits the specifications. 13, sum of digits is 1 + 3 = 4 which is not prime 26, sum of digits is 2 + 6 = 8 which is not prime 39, sum of digits is 3 + 9 = 12 which is not prime 52, sum of digits is 5 + 2 = 7 which is prime So, 52 is the smallest positive multiple of 13 for which the sum of its digits is prime.
33
Yes, yes, and no. 3- sum of digits must be multiple of 3. 6- sum of digits must be multiple of 3 and number must be even (multiple of 2). 9- sum of digits must be multiple of 9. (The sum of the digits here is 21.)
You could be 22? 2 + 2 = 4 2 x 2 = 4
The sum of the digits is a multiple of 3
The sum of the digits is a multiple of 9
The sum of the digits is also a multiple of 9. And, if the sum of the digits is too large, you can sum those digits and keep going.
A number is divisible by 3 if the sum of its digits is a multiple of 3. A number is divisible by 6 if the sum of its digits is a multiple of 3 and it's even. A number is divisible by 9 if the sum of its digits is a multiple of 9.
88
If the sum of the digits of a given number equals nine or a multiple of nine, nine is a factor of that number.
420
No factor of 9 has three digits. 450 is a three-digit multiple of 150 (and of 9) with a digit sum of 9.
Start with the smallest multiple of 13 and continue with the next smallest until finding one that fits the specifications. 13, sum of digits is 1 + 3 = 4 which is not prime 26, sum of digits is 2 + 6 = 8 which is not prime 39, sum of digits is 3 + 9 = 12 which is not prime 52, sum of digits is 5 + 2 = 7 which is prime So, 52 is the smallest positive multiple of 13 for which the sum of its digits is prime.