Working systematically

There are 604 NRICH Mathematical resources connected to Working systematically
Factor-Multiple Chains
problem
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Factor-multiple chains

Age
7 to 11
Challenge level
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Can you see how these factor-multiple chains work? Find the chain which contains the smallest possible numbers. How about the largest possible numbers?
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?
Jig Shapes
problem
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Jig shapes

Age
5 to 11
Challenge level
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Can you each work out what shape you have part of on your card? What will the rest of it look like?

missing multipliers
problem
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Missing multipliers

Age
7 to 14
Challenge level
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What is the smallest number of answers you need to reveal in order to work out the missing headers?
Maze 100
problem
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Maze 100

Age
7 to 11
Challenge level
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Can you go through this maze so that the numbers you pass add to exactly 100?
Wonky Watches
problem
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Wonky watches

Age
7 to 11
Challenge level
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Stuart's watch loses two minutes every hour. Adam's watch gains one minute every hour. Use the information to work out what time (the real time) they arrived at the airport.

Multiplication Squares
problem
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Multiplication squares

Age
7 to 11
Challenge level
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Can you work out the arrangement of the digits in the square so that the given products are correct? The numbers 1 - 9 may be used once and once only.

Peaches today, Peaches tomorrow...
problem
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Peaches today, peaches tomorrow...

Age
11 to 14
Challenge level
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A monkey with peaches, keeps a fraction of them each day, gives the rest away, and then eats one. How long can his peaches last?
Andy's Marbles
problem
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Andy's marbles

Age
7 to 11
Challenge level
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Andy had a big bag of marbles but unfortunately the bottom of it split and all the marbles spilled out. Use the information to find out how many there were in the bag originally.

Nine-Pin Triangles
problem
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Nine-pin triangles

Age
7 to 11
Challenge level
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How many different triangles can you make on a circular pegboard that has nine pegs?