Exploring and noticing

There are 412 NRICH Mathematical resources connected to Exploring and noticing
Sums of Pairs
problem
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Sums of pairs

Age
11 to 16
Challenge level
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Jo has three numbers which she adds together in pairs. When she does this she has three different totals: 11, 17 and 22 What are the three numbers Jo had to start with?”
Twisting and Turning
problem
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Twisting and turning

Age
11 to 14
Challenge level
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Take a look at the video and try to find a sequence of moves that will untangle the ropes.
Crossed Ends
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Crossed ends

Age
11 to 14
Challenge level
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Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?
Cyclic Quadrilaterals
problem
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Cyclic quadrilaterals

Age
11 to 16
Challenge level
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Draw some quadrilaterals on a 9-point circle and work out the angles. Is there a theorem?

Dotty Six
problem
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Dotty six

Age
5 to 11
Challenge level
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Dotty Six is a simple dice game that you can adapt in many ways.

Biscuit Decorations
problem
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Biscuit decorations

Age
5 to 7
Challenge level
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Andrew decorated 20 biscuits to take to a party. He lined them up and put icing on every second biscuit and different decorations on other biscuits. How many biscuits weren't decorated?
One to Eight
problem
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One to eight

Age
11 to 14
Challenge level
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Complete the following expressions so that each one gives a four digit number as the product of two two digit numbers and uses the digits 1 to 8 once and only once.
Egyptian Rope
problem
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Egyptian rope

Age
7 to 11
Challenge level
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The ancient Egyptians were said to make right-angled triangles using a rope with twelve equal sections divided by knots. What other triangles could you make if you had a rope like this?

Frogs
problem
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Frogs

Age
11 to 14
Challenge level
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How many moves does it take to swap over some red and blue frogs? Do you have a method?
Eggs in Baskets
problem
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Eggs in baskets

Age
5 to 7
Challenge level
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There are three baskets, a brown one, a red one and a pink one, holding a total of 10 eggs. How many eggs are in each basket?