That they add up to 9
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.)
630
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.
Add the digits together. The sum of the digits of 23 is 5.
No factor of 9 has three digits. 450 is a three-digit multiple of 150 (and of 9) with a digit sum of 9.
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.)
630
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.
Add the digits together. The sum of the digits of 23 is 5.
If the sum of the digits of a given number equals nine or a multiple of nine, nine is a factor of that number.
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.
22
Add the digits together. The sum of the digits of 23 is 5.