Multiplication and division

There are 238 NRICH Mathematical resources connected to Multiplication and division
The Number Crunching Machine
problem

The number crunching machine

Age
7 to 11
Challenge level
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Put a number at the top of the machine and collect a number at the bottom. What do you get? Which numbers get back to themselves?
Cows and Sheep
problem

Cows and sheep

Age
7 to 11
Challenge level
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Use your logical reasoning to work out how many cows and how many sheep there are in each field.
As Easy as 1,2,3
problem

As easy as 1,2,3

Age
11 to 14
Challenge level
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When I type a sequence of letters my calculator gives the product of all the numbers in the corresponding memories. What numbers should I store so that when I type 'ONE' it returns 1, and when I type 'TWO' it returns 2, and so on.
Next Number
problem

Next number

Age
7 to 11
Challenge level
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Find the next number in this pattern: 3, 7, 19, 55 ...
1, 2, 3, 4, 5
problem

1, 2, 3, 4, 5

Age
7 to 11
Challenge level
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Using the numbers 1, 2, 3, 4 and 5 once and only once, and the operations x and ÷ once and only once, what is the smallest whole number you can make?
Rabbits in the pen
problem

Rabbits in the pen

Age
7 to 11
Challenge level
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Using the statements, can you work out how many of each type of rabbit there are in these pens?
Starfish Spotting
problem

Starfish spotting

Age
5 to 7
Challenge level
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How many starfish could there be on the beach, and how many children, if I can see 28 arms?
Sam's Quick Sum
problem

Sam's quick sum

Age
7 to 11
Challenge level
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What is the sum of all the three digit whole numbers?
Largest Number
problem

Largest number

Age
11 to 14
Challenge level
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What is the largest number you can make using the three digits 2, 3 and 4 in any way you like, using any operations you like? You can only use each digit once.
A Conversation Piece
problem

A conversation piece

Age
7 to 11
Challenge level
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Take the number 6 469 693 230 and divide it by the first ten prime numbers and you'll find the most beautiful, most magic of all numbers. What is it?