Creating and manipulating expressions and formulae

There are 198 NRICH Mathematical resources connected to Creating and manipulating expressions and formulae
Fibonacci Factors
problem

Fibonacci factors

Age
16 to 18
Challenge level
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For which values of n is the Fibonacci number fn even? Which Fibonnaci numbers are divisible by 3?
Triangles within Pentagons
problem

Triangles within pentagons

Age
14 to 16
Challenge level
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Show that all pentagonal numbers are one third of a triangular number.
Operating machines
problem

Operating machines

Age
16 to 18
Challenge level
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What functions can you make using the function machines RECIPROCAL and PRODUCT and the operator machines DIFF and INT?
The Simple Life
problem

The simple life

Age
11 to 14
Challenge level
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The answer is $5x+8y$... What was the question?
Magic squares for special occasions
article

Magic squares for special occasions

This article explains how to make your own magic square to mark a special occasion with the special date of your choice on the top line.
Reaction rates!
article

Reaction rates!

Fancy learning a bit more about rates of reaction, but don't know where to look? Come inside and find out more...
Telescoping Functions
article

Telescoping functions

Take a complicated fraction with the product of five quartics top and bottom and reduce this to a whole number. This is a numerical example involving some clever algebra.