Arithmagons can make ideal starters or plenaries as well as being used for a main lesson activity.
What is an arithmagon? (Updated August 2017)
Clearly the numbers in the rectangles are the sum of the numbers in the adjacent circles. Of course there is no need to use addition and no need to use triangular arithmagons!
These could used with students of all ages. Young children could practice basic skills or students studying advanced Mathematics could look at Calculus or Complex Numbers for example.
The challenge is of course to go backwards…
(Going backwards in Mathematics really helps understanding)
Nrich have some very useful resources including this introduction to arithmagons which includes an interactive allowing numbers to be changed and would work well on an interactive whiteboard. See also these further Nrich resources – this on multiplication and for older students a rather more advanced multiplication arithmagon using complex numbers. Also on Nrich, Irrational Arithmagons.
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