problem
1 out of 3
Flow Chart
Age
11 to 14
Challenge level
1 out of 3
The flow chart requires two numbers, M and N. Select several values for M and try to establish what the flow chart does.
problem
1 out of 3
Favourite
Substitution Cipher
Age
11 to 14
Challenge level
1 out of 3
Find the frequency distribution for ordinary English, and use it to help you crack the code.
problem
1 out of 3
Sorted
Age
14 to 18
Challenge level
1 out of 3
How can you quickly sort a suit of cards in order from Ace to King?
problem
2 out of 3
Zeller's Birthday
Age
14 to 16
Challenge level
2 out of 3
What day of the week were you born on? Do you know? Here's a way to find out.