Working systematically

There are 549 NRICH Mathematical resources connected to Working systematically
Forgot the Numbers
problem

Forgot the Numbers

Age
7 to 11
Challenge level
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On my calculator I divided one whole number by another whole number and got the answer 3.125. If the numbers are both under 50, what are they?
Abundant Numbers
problem

Abundant Numbers

Age
7 to 11
Challenge level
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48 is called an abundant number because it is less than the sum of its factors (without itself). Can you find some more abundant numbers?
Wag Worms
problem

Wag Worms

Age
7 to 11
Challenge level
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When intergalactic Wag Worms are born they look just like a cube. Each year they grow another cube in any direction. Find all the shapes that five-year-old Wag Worms can be.
Zios and Zepts
problem

Zios and Zepts

Age
7 to 11
Challenge level
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On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?
Waiting for Blast Off
problem

Waiting for Blast Off

Age
7 to 11
Challenge level
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10 space travellers are waiting to board their spaceships. There are two rows of seats in the waiting room. Using the rules, where are they all sitting? Can you find all the possible ways?
Wonky Watches
problem

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.
Pasta Timing
problem

Pasta Timing

Age
7 to 11
Challenge level
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Nina must cook some pasta for 15 minutes but she only has a 7-minute sand-timer and an 11-minute sand-timer. How can she use these timers to measure exactly 15 minutes?
Knight's Swap
problem

Knight's Swap

Age
7 to 11
Challenge level
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Swap the stars with the moons, using only knights' moves (as on a chess board). What is the smallest number of moves possible?
Read This Page
problem

Read This Page

Age
11 to 14
Challenge level
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Replace the letters with numbers to make the addition work out correctly. R E A D + T H I S = P A G E
Map Folding
problem

Map Folding

Age
7 to 11
Challenge level
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Take a rectangle of paper and fold it in half, and half again, to make four smaller rectangles. How many different ways can you fold it up?