Put one of the letters C, L, X, V, I into each cell of a 5 × 5 grid so that each row and each column is a valid five-letter Roman numeral less than 300. No numeral may appear more than once; the five horizontal numerals should be in descending numerical order from top to bottom, and the five vertical numerals in descending numerical order from left to right.
What is the sum of your 10 Roman numerals (expressed in ordinary Arabic numerals)?
WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 25 March. The Editor's decision is final. Please send entries to Enigma 1533, New Scientist, Lacon House, 84 Theobald's Road, London WC1X 8NS, or to
Answer to 1527 Square from primes: (a) 11449 (b) 19881
The winner Peter Kaufeler of London, UK
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