These puzzles appeared in Issue 02 of the magazine.
Source: My Best Puzzles in Mathematics by Hubert Phillips
I’m thinking of a number. I’ve squared it. I’ve squared the square. And I’ve multiplied the second square by the original number.
So I now have a number of seven digits whose final digit is a seven.
What was my original number?
How many square numbers are there whose digits are all odd?
Folding Tube Maps
The resulting tetrahedron is almost (but not quite) regular.
What ratio would the sides of the tube maps have to be to make a regular tetrahedron?
You might also like…
- We feel underdressed for Breakfast at Villani's
- Did you win?
- Write down a quadratic. What is the probability that it factorises? Paging Prof. Dirichet...
- We have a go at the puzzles in Daniel Griller's new book
- Read more about the fire-breathing curves that appear on the cover of issue 05
- How many did you spot?