Combinations

There are 153 NRICH Mathematical resources connected to Combinations
Spectrometry detective
problem

Spectrometry detective

Age
16 to 18
Challenge level
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From the atomic masses recorded in a mass spectrometry analysis can you deduce the possible form of these compounds?
Cereal Packets
problem

Cereal packets

Age
7 to 11
Challenge level
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How can you put five cereal packets together to make different shapes if you must put them face-to-face?
Ice Cream
problem

Ice cream

Age
7 to 11
Challenge level
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You cannot choose a selection of ice cream flavours that includes totally what someone has already chosen. Have a go and find all the different ways in which seven children can have ice cream.
Jumping Cricket
problem

Jumping cricket

Age
5 to 7
Challenge level
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El Crico the cricket has to cross a square patio to get home. He can jump the length of one tile, two tiles and three tiles. Can you find a path that would get El Crico home in three jumps?
Painting Cubes
problem

Painting cubes

Age
11 to 14
Challenge level
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Imagine you have six different colours of paint. You paint a cube using a different colour for each of the six faces. How many different cubes can be painted using the same set of six colours?
Football crazy Hockey mad
problem

Football crazy hockey mad

Age
11 to 14
Challenge level
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In a league of 5 football teams which play in a round robin tournament show that it is possible for all five teams to be league leaders.
Throw a 100
problem

Throw a 100

Age
7 to 11
Challenge level
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Can you score 100 by throwing rings on this board? Is there more than way to do it?
Semaphore Signals
problem

Semaphore signals

Age
7 to 11
Challenge level
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Semaphore is a way to signal the alphabet using two flags. You might want to send a message that contains more than just letters. How many other symbols could you send using this code?
Flora the Florist
problem

Flora the florist

Age
14 to 16
Challenge level
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Flora has roses in three colours. What is the greatest number of identical bunches she can make, using all the flowers?
Placeholder: several colourful numbers
article

Binomial coefficients

An introduction to the binomial coefficient, and exploration of some of the formulae it satisfies.