
Multiplication and division
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problem
A conversation piece
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? -
problem
1, 2, 3, 4, 5
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? -
problem
The number crunching machine
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? -
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problem
Which is quicker?
Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?
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problem
Remainders
I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?
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problem
Code breaker
This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code? -
problem
The clockmaker's birthday cake
The clockmaker's wife cut up his birthday cake to look like a clock face. Can you work out who received each piece?