problem Neighbourly Addition Age 7 to 14 Challenge level I added together some of my neighbours' house numbers. Can you explain the patterns I noticed?
problem Magic Crosses Age 7 to 14 Challenge level Can you find examples of magic crosses? Can you find all the possibilities?
problem What Could \It Be? Age 5 to 7 Challenge level In this calculation, the box represents a missing digit. What could the digit be? What would the solution be in each case?
problem Play to 37 Age 7 to 11 Challenge level In this game for two players, the idea is to take it in turns to choose 1, 3, 5 or 7. The winner is the first to make the total 37.
problem Sorting the Numbers Age 7 to 11 Challenge level Can you put the numbers in the correct place in this Carroll diagram?
problem Square subtraction Age 7 to 11 Challenge level Look at what happens when you take a number, square it and subtract your answer. What kind of number do you get? Can you prove it?
problem Take three numbers Age 7 to 11 Challenge level What happens when you add three numbers together? Will your answer be odd or even? How do you know?
problem Odd times Even Age 5 to 7 Challenge level This problem looks at how one example of your choice can show something about the general structure of multiplication.
problem Two numbers under the microscope Age 5 to 7 Challenge level This investigates one particular property of number by looking closely at an example of adding two odd numbers together.
problem Magic Letters Age 11 to 14 Challenge level Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?