Permutations

There are 18 NRICH Mathematical resources connected to Permutations
Placeholder: several colourful numbers
problem

ip?

Age
16 to 18
Challenge level
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Seventh challenge cipher
Colourful Tiles
problem

Colourful Tiles

Age
11 to 14
Challenge level
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Weekly Problem 21 - 2011
How many ways can you paint this wall with four different colours?
Bell Ringing
problem

Bell Ringing

Age
11 to 14
Challenge level
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Suppose you are a bellringer. Can you find the changes so that, starting and ending with a round, all the 24 possible permutations are rung once each and only once?
Even Up
problem

Even Up

Age
11 to 14
Challenge level
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Consider all of the five digit numbers which we can form using only the digits 2, 4, 6 and 8. If these numbers are arranged in ascending order, what is the 512th number?
Voting Paradox
problem

Voting Paradox

Age
14 to 18
Challenge level
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Some relationships are transitive, such as `if A>B and B>C then it follows that A>C', but some are not. In a voting system, if A beats B and B beats C should we expect A to beat C?
Six times five
problem

Six times five

Age
11 to 14
Challenge level
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How many six digit numbers are there which DO NOT contain a 5?
396
problem

396

Age
14 to 16
Challenge level
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The four digits 5, 6, 7 and 8 are put at random in the spaces of the number : 3 _ 1 _ 4 _ 0 _ 9 2 Calculate the probability that the answer will be a multiple of 396.
Chances are
problem

Chances are

Age
14 to 16
Challenge level
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Which of these games would you play to give yourself the best possible chance of winning a prize?
Master Minding
problem

Master Minding

Age
11 to 14
Challenge level
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Your partner chooses two beads and places them side by side behind a screen. What is the minimum number of guesses you would need to be sure of guessing the two beads and their positions?