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Farey Sequences

11 to 14

There are lots of ideas to explore in these sequences of ordered fractions.

problem

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Three Neighbours

7 to 14

Take three consecutive numbers and add them together. What do you notice?

article

Genetic Intrigue

16 to 18

Dip your toe into the fascinating topic of genetics. From Mendel's theories to some cutting edge experimental techniques, this article gives an insight into some of the processes underlying a fundamental biological discipline.

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Table Patterns Go Wild!

7 to 11

Nearly all of us have made table patterns on hundred squares, that is 10 by 10 grids. This problem looks at the patterns on differently sized square grids.

$Probability through Problems: a \new \approach to \teaching \probability$

article

Probability Through Problems: A New Approach to Teaching Probability

11 to 16

problem

Tessellating Triangles

7 to 11

Can you make these equilateral triangles fit together to cover the paper without any gaps between them? Can you tessellate isosceles triangles?

problem

Overlapping Squares

7 to 11

Have a good look at these images. Can you describe what is happening? There are plenty more images like this on NRICH's Exploring Squares CD.

problem

Bina-Ring

16 to 18

Investigate powers of numbers of the form (1 + sqrt 2).

problem

Molecular Sequencer

14 to 18

Investigate the molecular masses in this sequence of molecules and deduce which molecule has been analysed in the mass spectrometer.

problem

Cashing Up

5 to 11

What is the most common coin in this shopkeeper's till?