Christmaths Advent Calendar 2013: Day 4

This year’s Christmaths Advent Calendar will have a question for every day in December up to and including Christmas Day, each one featuring a new mathematical challenge.

Mary and Jason were making propellers for their wooden helicopters.


Mary put the number 1961 on her propeller and noticed that when she turned the propeller she had the same number.

Jason was trying to think of a number that he could put on his that had the same rotational symmetry (it looks the same when turned upside down).

What is the next larger number that has this property?

Got an answer? Please leave a comment below.

Mr Pitts currently teaches Computing to the whole school along with some other subjects during teacher's PPA time. He runs this website and makes sure it all works smoothly, most of the time!


  1. Clough
    Wednesday, December 4th 2013 @ 17:51

    Is it 6009?

    • Mr Pitts
      Wednesday, December 4th 2013 @ 20:02

      It is as only the numbers 0, 1, 6, 8 or 9 have rotational symmetry so that’s limits the possibilities.