2, 4, 6, 8, 10, 12
1 is the number less than fifty with the fewest number of factors. All other numbers have at least two factors (1, and the integer itself).
11, 13, 17, 19
It can be. 13 is a factor of 26.
All the prime numbers less than 50 are such numbers, ie any of the 15 numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47.
The prime numbers that are less than 22 are 2, 3, 7, 11, 13, 17, 19.
It is a ratio of 5:13
Greater than. Positive numbers are greater than negative numbers.
Multiples of 13
For this kind of question, I would suggest looking up a table of prime numbers. As an alternative, you can try to find factors for each of the numbers - if it has a factor, it is NOT a prime. For this range of numbers, testing for prime numbers up to 13 is appropriate. (If 17 is a factor of one of these numbers, the other factor is less than 17, so you would already have found it before you reach 17.)
The set of prime numbers less than 20 = {2, 3, 5, 7, 11, 13, 17,19}
11 13 17 19.
1,2,3,4,5,6,7,8,9,10,11,12 Anything less than the number than your counting till. Like lets say The question is: Positive whole numbers less than 18. You would count all the numbers before 18, But NOT 18. :) Bye!