You may also like

problem icon

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?

problem icon

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?

problem icon

What an Odd Fact(or)

Can you show that 1^99 + 2^99 + 3^99 + 4^99 + 5^99 is divisible by 5?

Repeaters

Age 11 to 14 Challenge Level:


Choose any 3 digits and make a 6 digit number by repeating the 3 digits in the same order (e.g. 594594).

Whatever digits you choose the number will always be divisible by 7 and by 11 and by 13, in each case without a remainder.

Can you explain why?