Duality is an important concept in understanding mathematical problems. Sometimes a problem can be ‘reveresed’ by considering it’s dual, for example swapping around lines and points in a triangle. This Powerpoint looks at how duality appears in the following contexts division and subtraction 2D shapes and 3D shapes 2D graphs including the Fano Plane

Magic Squares are just the beginning! A Latin square is a grid where each symbol appears exactly once in each row a column - recognisable to most pupils as being like a Su Doku. This resources extends that idea to look at double and further Latin Squares. These are useful for many things (see e.g. my other resource on Dobble)

A colourful poweroint introducing a new idea for most pupils. In standard 2D geometry parallel lines never meet. In projective geometry we add an extra point (infinity) where the lines meet. This turns out to be useful for various problems (e.g. see my other resource on Dobble).