What's in a name?
Here's a very elementary code that requires young children to read a table, and look for similarities and differences.
Cracking codes
What's happening?
Shapes are added to other shapes. Can you see what is happening? What is the rule?
What was in the box?
This box does something to the numbers that go into it. If you know the numbers that come out, what might be going on inside the box?
It's a scrabble
Letters have different values in Scrabble - how are they decided upon? And would the values be the same for other languages?
Unlocking the case
Some secret codes
Make 24
Substitution transposed
The best card trick?
Time for a little mathemagic! Choose any five cards from a pack and show four of them to your partner. How can they work out the fifth?
Substitution cipher
Find the frequency distribution for ordinary English, and use it to help you crack the code.
Secondary cipher challenge part 1
Transposition cipher
Keeping it safe and quiet
Secret transmissions
How can Agent X transmit data on a faulty line and be sure that her message will get through?
Probably a code?
Is the regularity shown in this encoded message noise or structure?
Stage 5 cipher challenge
More secret transmissions