How well do you know your prime numbers? Challenge your friends to this Sporcle quiz!
Here is a great phone app that will help you with your arithmetic so you don’t need to be afraid when you are faced with that non-calculator exam. It’s called Maths Tricks and shows you lots of short cuts to performing calculations and gives you endless practice to improve your speed and accuracy. Best of all it’s free!
You can find it on Google Play. I am recommending this because it is good, not because I have any connection to the app.
Have a go at this worksheet to find all the Prime Numbers less than 100.
Now try this much bigger Sieve to find all the Prime Numbers less than 400! Start by clicking on 2 and all the multiples of 2 will be removed. Then click on 3 to remove the multiples of 3 and continue clicking on the prime numbers until you are only left with red prime numbers.
Also take a look at this video
Here’s another great starter from Transum