If you multiply me by any other single-digit number, the sum of the individual digits of the resulting product will always equal me. What number am I?
9
Any integer multiplied by 9 yields a product whose digits sum to 9 (e.g., 9 x 4 = 36, and 3 + 6 = 9; 9 x 7 = 63, and 6 + 3 = 9).
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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