You may also like

problem icon

Lastly - Well

What are the last two digits of 2^(2^2003)?

problem icon

Counting Factors

Is there an efficient way to work out how many factors a large number has?

problem icon

Summing Consecutive Numbers

15 = 7 + 8 and 10 = 1 + 2 + 3 + 4. Can you say which numbers can be expressed as the sum of two or more consecutive integers?

Slippy Numbers

Age 11 to 14 Challenge Level:

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.

Find slippy numbers ending in 4 (a small one) and in 2 and 3 (larger ones).

Explain why the slippy number ending in 9 has a unique sequence of digits; can there be more than one slippy number ending in 9?

You might like to write a short program to find other slippy numbers.