Exploring and noticing

There are 412 NRICH Mathematical resources connected to Exploring and noticing
Differences
problem
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Differences

Age
11 to 14
Challenge level
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Can you guarantee that, for any three numbers you choose, the product of their differences will always be an even number?
Prison Cells
problem
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Prison cells

Age
7 to 11
Challenge level
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There are 78 prisoners in a square cell block of twelve cells. The clever prison warder arranged them so there were 25 along each wall of the prison block. How did he do it?
Numerically Equal
problem
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Numerically equal

Age
7 to 11
Challenge level
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Can you draw a square in which the perimeter is numerically equal to the area?

Shopping Basket
problem
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Shopping basket

Age
11 to 16
Challenge level
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The items in the shopping basket add and multiply to give the same amount. What could their prices be?
Pick's Theorem
problem
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Pick's theorem

Age
14 to 16
Challenge level
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Polygons drawn on square dotty paper have dots on their perimeter (p) and often internal (i) ones as well. Find a relationship between p, i and the area of the polygons.
Special Numbers
problem
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Special numbers

Age
11 to 14
Challenge level
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My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?

Mixing Paints
problem
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Mixing paints

Age
11 to 14
Challenge level
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Can you work out how to produce different shades of pink paint?
Sort the Street
problem
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Sort the street

Age
5 to 7
Challenge level
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Sort the houses in my street into different groups. Can you do it in any other ways?

A Chance to Win?
problem
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A chance to win?

Age
11 to 14
Challenge level
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Imagine you were given the chance to win some money... and imagine you had nothing to lose...
In the bag
problem
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In the bag

Age
11 to 14
Challenge level
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Can you guess the colours of the 10 marbles in the bag? Can you develop an effective strategy for reaching 1000 points in the least number of rounds?