Prime numbers
Prime numbers are numbers that can only be divided by themselves and one. If a number is a multiple of any other number, then it is not a prime.
Prime numbers from 1 - 100
- Question
Can you find all the prime numbers between 1 and 100?
Hints
Remember, a prime numbers can only be divided by itself and 1.
You can use your knowledge of multiples (times tables) to eliminate numbers.
Start with the smallest numbers and work your way up.
It might help if you draw out a grid so you can spot any patterns.
Here's one way to find all the prime numbers.
- 2 is the first prime number. All the other even numbers can be divided by 2, so no other even numbers are prime.
- 3 is the next prime number. Work out all the multiples of 3, (6, 9, 12, 15 etc) and forget about these. None of them are primes.
- 5 is the next prime. No other multiples of 5 are primes.
- Keep going with the other primes (7, 11, 13 etc), removing all the multiples of these as you go.
You should end up with a list of 25 prime numbers between 1 and 100. These are shown in the grid below.