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For ideas on how this problem and others from the Dotty Grids Collections can be used in the classroom, you may be interested to read this article.
A printable version of this problem is available as a Word or Pdf file.
15 = 7 + 8 and 10 = 1 + 2 + 3 + 4. Can you say which numbers can be expressed as the sum of two or more consecutive integers?
A picture is made by joining five small quadrilaterals together to make a large quadrilateral. Is it possible to draw a similar picture if all the small quadrilaterals are cyclic?
It is impossible to trisect an angle using only ruler and compasses but it can be done using a carpenter's square.