Games with car number plates
The first book I have read on holiday (to the general derision of my family) was Genna Sosonko's The World Champions I knew, a series of mini-bios on several world chess champions (cue 'I had a boring life with no friends' quips from my chess widow wife, to much accompanying mirth from la famille).
The longest, and probably the warmest, is of Mikhail Tal. I am pleased to say that I have at least one thing in common with the Magician from Riga, namely a love of crosswords, brain teasers, and numbers (Sosonko, pg 170).
Genna writes that he learnt a game from Mikhail: out of four figures on the number plate of a car, make 21, using each figure only once. Sosonko writes 'in complicated situations he dealt with square roots, differentials, and integrals with a triumphant look on his face'.
Now I have no idea how differentials and integrals can be applied to numbers. So ignoring them, and instead making the rules:
- All the digits must be used, once and only once;
- The only operations are addition, subtraction, division, multiplication and squaring;
I tried it on our hire car number plate here in Kas, Turkey. The numbers are 5263 and…. alas, I can't do it.
A bit like not being able to solve most of Mikhail's fabulous combinations.

Allan! (6 x 3) + 5 – 2
Notes hopefully on the way today – enjoy your holiday!
6^2 – (5*3)
(5*6) – (3^2)
(2+5) * (6/3)
Hmm – 3 out of 4 isn’t so bad – ignore that last attempt!