numbers the anaesthetist

Today is the 20th of July.

Twenty was the number used as the base for counting in the ancient Mayan and Aztec civilizations. It has been suggested that 20 was the natural base to use in hot climates where the toes were kept uncovered and easily accessible to help the fingers get past 10.

The only numero-linguistic pieces of evidence of barefoot Britons, however, are the 20 shillings in a pound and the word "score" signifying 20, although that is more likely to have represented a tally, or score, on a stick than a full set of fingers and toes.

The shoeless Germans, however, used the word Stiege to mean 20 eggs, sheep or yards of cloth, and Schneise meaning a rope on which 20 codfish could be hung to dry.

Now of my threescore years and ten,

Twenty will not come again,

And take from seventy springs a score,

It leaves me only fifty more.

(Housman, A Shropshire Lad).

Twenty is the number of faces on an icosahedron and the number of vertices on a dodecahedron.

Twenty is also:

The weight of the average iceberg in tons;

The area, in square feet, of an average person's skin;

The percentage of the world's carrots grown in China.

Competition: The mixed doubles are back on court this week. The following sentence holds the key to three words, linked by a common theme.

Pelt numb tables; arise heroic pith.

Group the words into three pairs, then re-arrange the letters within each pair. We have three Chambers Dictionary prizes for correct answers received by 1 August. Entries to: Pastimes, the Independent, 1 Canada Sq, Canary Wharf, London E14 5DL.

6 July answers and prizes:

Wimbledon (mind below) Tennis (nest in) Championships (Chopin's mishap). Winners: Lucy Bowden, Mrs J Metcalfe, Colin Bedford.