Challenge Level

Look for the common features in these graphs. Which graphs belong together?

Challenge Level

A polite number can be written as the sum of two or more consecutive positive integers, for example 8+9+10=27 is a polite number. Can you find some more polite, and impolite, numbers?

Challenge Level

Which of these triangular jigsaws are impossible to finish?

Challenge Level

Can you make matrices which will fix one lucky vector and crush another to zero?

Challenge Level

Charlie likes to go for walks around a square park, while Alison likes to cut across diagonally. Can you find relationships between the vectors they walk along?