Internet Math Challenge

Solution to the puzzle for 14 November 2003

There are four correct answers to this one. It's mostly a process of deduction and eliminating possibilities to find them. A good place to start is this: the only way that the sum of two five-digit numbers and one four-digit number can be a six-digit number is for the first digit of the sum to be either 1 or 2. So, the letter E must stand for either 1 or 2. If you try E=2 you soon run into trouble, so in fact E must be 1. This gives:

From here you just try various possibilities. For example, the second column shows that the letter U must be either 8 or 9 (depending on whether or not the sum of the first column was more than 9). Trying R=8 and R=9 soon leads to trouble, so the sum of the first column is less than 10 which means that U must be 9. It's somewhat tedious to account for all of the possibilities, but if you do, you find only the four solutions given below.

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