The pied piper
I found an old eight-digit calculator. As usual, each position of the display consisted of seven light segments 鈥� with, for example, seven lighting up to display an 鈥�8鈥� and four lighting up to display a 鈥�4鈥�.
To see if it still worked, I typed in the approximation for 蟺, namely 22/7, and found that I saw a number, but not the correct one. After some investigation I found that one of the 56 segments always failed to light. I then used 22/7 again to calculate approximations for 2蟺, 3蟺, 4蟺, 5蟺, 6蟺, 7蟺, 8蟺, 9蟺 and 10蟺.
In two-thirds or more of these cases the answer looked like a number, but (a) how many of them were correct? and (b) what was the original eight-digit number seen in the display?
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WIN 拢15 will be awarded to the sender of the first correct answer opened on Wednesday 20 June. The Editor鈥檚 decision is final. Please send entries to Enigma 1698, New 女生小视频, Lacon House, 84 Theobald鈥檚 Road, London WC1X 8NS, or to enigma@newscientist.com (please include your postal address).
Answer to 1692 Key factors: the number is 436578912
The winner John Kelly of Walsall, West Midlands, UK
