**From New Scientist #2624, 6th October 2007**

I have placed each of the digits 1 to 9 in a 3 by 3 grid, with one digit in each little box. So I can read off 12 three-figure numbers; three from left to right across the rows, three from right to left, three from top to bottom in the columns, and three from bottom to top.

Now for each digit, D say, I have counted how many of those 12 numbers are exactly divisible by D. In each case the answer is itself divisible by D.

What are the highest and lowest of the 12 three-figure numbers?

[enigma1463]

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This Python program runs in 730ms.

Solution:The highest number is 971. The lowest number is 164.