Draw some quadrilaterals on a 9-point circle and work out the angles. Is there a theorem?
Explore the relationships between different paper sizes.
Find the sum of this series of surds.
Can you work out the irrational numbers that belong in the circles to make the multiplication arithmagon correct?
Five equations... five unknowns... can you solve the system?
What do you get when you raise a quadratic to the power of a quadratic?
By sketching a graph of a continuous increasing function, can you prove a useful result about integrals?
Use graphs to gain insights into an area and perimeter problem, or use your knowledge of area and perimeter to gain insights into the graphs...