# Mathematical Curiosity Shop

### Lucky Thirteen

Apart from the fact that they are equal, ONE PLUS TWELVE and TWO PLUS ELEVEN are anagrams of each other.

### Fascinating Numbers

*Henry M Chinheya
Gokomere High School, Zimbabwe*

Visiting the great Indian mathematician Srinivasa Ramanujan in hospital, his friend G H Hardy remarked that the number of his taxi had been 1729, surely a dull number. Ramanujan replied, 'No, it is a very interesting number. It is the smallest number expressible as a sum of two cubes in two different ways'.

1729 = 10^{3} + 9^{3} = 12^{3} + 1^{3}

Ramanujan was fascinated by numbers, and it is no surprise that he found some weird approximations for . You can check the following example easily with a calculator:

### How Odd!

The number of odd digits in an odd number expressed in an odd base is odd.

### The Wobble Number

*Robin Hall, Michaelhouse*

While the earth's North Pole points to to the pole star at present, in fact due to a'wobble' in the earth's spin this changes continuously, and it will take 25920 years to return to the exact position.

The number 25920 is not of course exact, but is probably accurate to the nearest ten years. The problem in obtaining a more accurate figure makes the mind boggle. The change is 0.0139 degrees per year, which is 0.8333 minutes or a mere 50 arc seconds.

The number 25920 is interesting for another reason: it is equal to 2^{6}×3^{4}×5^{1}, incorporating each of the first six digits once only.