**From New Scientist #2612, 14th July 2007**

I have created a sum by adding a three-digit number consisting solely of odd digits to a three-digit number consisting solely of even digits to make a three-digit number in which odd and even digits alternate. The nine digits used are all different. If I tell you any of my three numbers you will be able to deduce with certainty what the other two numbers are.

What are the three numbers of my sum?

**Enigma 1721** is also called “Odds and evens”.

[enigma1451]

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Solution:The three numbers in your sum are 359, 402 and 761.