- "I think a Christmas-card, drawn by the child herself who sends it, is worth ever so much more than a bought one."
- Lewis Carroll, Letter to Edith [Blakemore], 27 Dec. 1881

An attitude with which I can wholeheartedly agree.

## Math puzzle for Wilton John Rix

Lewis Carroll wrote this cute puzzle for the eldest son of a good friend.

[To] Mr. Wilton Rix, Esq., P.M., L.S.D., P.P.C., etc., etc., Bank House, Beccles

- May 20, 1885

- Honoured Sir,

- Understanding you to be a distinguished algebraist (i.e. distinguished from other algebraists by different face, different height, etc.) I beg to submit to you a difficulty which distresses me much.

- If x and y are each equal to "1," it is plain that 2 × (x² – y²) = 0, and also that 5 × (x - y) = 0. Hence 2 × (x² – y²) = 5 × (x – y).
- Now divide each side of this equation by (x – y).
- Then 2 × (x + y) = 5.
- But (x + y) = (1 + 1), i.e. = 2.
- So that 2 × 2 = 5.
- Ever since this painful fact has been forced upon me, I have not slept more than 8 hours a night, and have not been able to eat more than 3 meals a day.
- I trust you will pity me and will kindly explain the difficulty to

- Your obliged,
- Lewis Carroll