Divisibility

There are 75 NRICH Mathematical resources connected to Divisibility
What an odd fact(or)
problem
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What an odd fact(or)

Age
11 to 14
Challenge level
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Can you show that 1^99 + 2^99 + 3^99 + 4^99 + 5^99 is divisible by 5?
Elevenses
problem
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Elevenses

Age
11 to 14
Challenge level
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How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results?
Latin Numbers
problem
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Latin numbers

Age
14 to 16
Challenge level
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Can you create a Latin Square from multiples of a six digit number?
Why 24?
problem
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Why 24?

Age
14 to 16
Challenge level
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Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.
Power mad!
problem
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Power mad!

Age
11 to 14
Challenge level
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Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.

Counting Factors
problem
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Counting factors

Age
11 to 14
Challenge level
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Is there an efficient way to work out how many factors a large number has?
Going round in circles
problem
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Going round in circles

Age
11 to 14
Challenge level
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Mathematicians are always looking for efficient methods for solving problems. How efficient can you be?
The Remainders Game
game
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The remainders game

Play this game and see if you can figure out the computer's chosen number.

American Billions
problem
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American billions

Age
11 to 14
Challenge level
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Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...
Statement Snap
problem
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Statement snap

Age
7 to 14
Challenge level
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You'll need to know your number properties to win a game of Statement Snap...