Here are some of them: 21, 42, 63, 84, 105, 126, 147, 168.
When a number is a multiple of seven it is also divisible by seven.
510 is not divisible by seven.
The smallest number divisible by eight seven and five is 280.
If all the digits in a number add up to a number divisible by three, the number itself is divisible by three.For example the number 711: 7 + 1 + 1 = 9. Nine is divisible by three, therefore 711 is divisible by three.
Converse:If a number is divisible by 3, then every number of a digit is divisible by three. Inverse: If every digit of a number is not divisible by 3 then the number is not divisible by 3? Contrapositive:If a number is not divisible by 3, then every number of a digit is not divisible by three.
You would fill in the blank with the word sum, which means that you add each of the digits of the number. If that sum is divisible by three then the number is divisible by 3.
Seven
21 is the product of two prime numbers, three and seven. A prime number is defined as a number divisible only by one or itself. So ... NO ... 21 is not a prime number.
There is an infinite number of numbers that are not divisible by seven!
No.
No.
The greatest three digit number that is divisible by 7 is 994.