Multiplication and division

There are 227 NRICH Mathematical resources connected to Multiplication and division
Highest and Lowest
problem

Highest and Lowest

Age
7 to 11
Challenge level
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Put operations signs between the numbers 3 4 5 6 to make the highest possible number and lowest possible number.
How many eggs?
problem

How many eggs?

Age
7 to 11
Challenge level
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Peter, Melanie, Amil and Jack received a total of 38 chocolate eggs. Use the information to work out how many eggs each person had.
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.
Number rules - OK
problem

Number rules - OK

Age
14 to 16
Challenge level
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Can you produce convincing arguments that a selection of statements about numbers are true?
X marks the spot
problem

X marks the spot

Age
11 to 14
Challenge level
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When the number x 1 x x x is multiplied by 417 this gives the answer 9 x x x 0 5 7. Find the missing digits, each of which is represented by an "x" .
Powerful factorial
problem

Powerful factorial

Age
11 to 14
Challenge level
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6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest power of two that divides exactly into 100!?
Eminit
problem

Eminit

Age
11 to 14
Challenge level
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The number 8888...88M9999...99 is divisible by 7 and it starts with the digit 8 repeated 50 times and ends with the digit 9 repeated 50 times. What is the value of the digit M?
One O Five
problem

One O Five

Age
11 to 14
Challenge level
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You can work out the number someone else is thinking of as follows. Ask a friend to think of any natural number less than 100. Then ask them to tell you the remainders when this number is divided by 3, 5 and by 7...
3388
problem

3388

Age
11 to 14
Challenge level
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Using some or all of the operations of addition, subtraction, multiplication and division and using the digits 3, 3, 8 and 8 each once and only once make an expression equal to 24.
Slippy Numbers
problem

Slippy Numbers

Age
11 to 14
Challenge level
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The number 10112359550561797752808988764044943820224719 is called a 'slippy number' because, when the last digit 9 is moved to the front, the new number produced is the slippy number multiplied by 9.