Prime Numbers - exploration prior to teaching screens

Orientation

'Unseen' sorting is going on – the left hand box is for primes, the right hand for non-primes – but the user doesn't know what the rule is. Ten numbers are 'semi-randomly' chosen from the numbers 10–40, the non-random bit being that at least 4 of them should be prime. (Primes: 11, 13, 17, 19, 23, 29, 31, 37. Non-primes: 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40)

The user drags numbers into one or other of the boxes. Any correctly placed numbers remain in place and any incorrectly placed numbers are rejected and returned to the top of the screen. These movements can be accompanied by a sound effect.

RESET clears the boxes and gives a fresh set of numbers.
The HINT button gives the user a clue about what to think about.

Narrations

Instruction text:

These two boxes are for two different kinds of numbers.
Drag all the numbers into the boxes and see what happens.
Can you work out how the numbers are being sorted?
When you’ve seen enough, click on the Discover button to find out more.

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If:

The user clicks HINT

Voice:

Think about factors.

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