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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?


Choose any 3 digits and make a 6 digit number by repeating the 3 digits in the same order (e.g. 594594). Explain why whatever digits you choose the number will always be divisible by 7, 11 and 13.

Digit Sum

What is the sum of all the digits in all the integers from one to one million?

Just Repeat

Age 11 to 14 Challenge Level:

Just repeat!

Think of any three-digit number.
Repeat the digits


234 ....... 234 234

973 ...... 973 973

Both 6-digit numbers are divisible by 91.

Is this a coincidence?

Are there other patterns and connections?