It's also known as "lucky guess". While it is possible for a puzzle like that one to have one of the letters be zero, it is usually the case that one zero makes all zero. Plus, since we were only going for a right answer to the puzzle, I could have chose V=0 first, found it was not valid, then jumped back into V=9. But since I did V=9 first, and got a good answer, I could halt right there.
Oh, and by the way, I'm taking a pre-graduate level theoretical computer science course and a high level number theory course currently. Might have something to do with the intuition development
Narf:
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