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Even Up

Consider all of the five digit numbers which we can form using only the digits 2, 4, 6 and 8. If these numbers are arranged in ascending order, what is the 512th number?

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Double Digit

Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?

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Not a Polite Question

When asked how old she was, the teacher replied: My age in years is not prime but odd and when reversed and added to my age you have a perfect square...

As Easy as 1,2,3

Age 11 to 14 Challenge Level:

My calculator has 26 memories - one per letter of the alphabet. When I type a sequence of letters the calculator gives the product of all the numbers in the corresponding memories. I want to put numbers in the various stores so that when I type the word ONE it returns 1, and when I type the word TWO it returns 2, and when I type the word THREE it returns 3 and so on. How far can you get ? Is there an integer above which it is impossible to get ?