You'll come across many types of numbers in KS3 Maths  integers, natural numbers, fractions, even letters which are used in place of numbers in algebra. One set of numbers you are sure to encounter is the prime numbers.
So, what exactly is a prime number? Well a prime number is an integer (whole number) with exactly two factors  no more, no less. The factors are always the number itself and the number 1. That means that 2, 3, 5, 7 and 11 are the first five prime numbers. They don't appear on any of the times tables except their own. 1 is NOT a prime number. The reason is that primes MUST have TWO factors. The number 1 has only one factor  itself.
Try this quiz all about prime numbers to see if you understand what the term really means. Read each question well and be sure to understand it before you choose your answer. And don't forget the helpful comments which come after each question. They might help to explain anything you are unsure of. Good luck!














Prime is a word in its own right

All the numbers given (along with the correct answer, 8) can be divided into 24 with the result that the answer is a whole number


There are four factors of 14  the numbers 1, 2, 7 and 14. Because there are more than two factors, it cannot be a prime number

All the incorrect answers have three or more factors


The number 1 has only one factor  itself. Remember the rule, a prime number has TWO factors itself AND 1

15 can be divided by 3 and 5 as well as 1 and 15


35 appears in the 5 and the 7 times tables, 33 is in the 3 and 11 times tables and 39 (which may have tricked you) is divisible by 13 and 3

You'd do well to memorise the first 30 or so prime numbers


Unfortunately you have to either learn the numbers or work them out

1 and 101 are the only factors of 101 and therefore it is a prime number
