Multiply me by any whole number, and the sum of the digits in your answer will always reduce back to me if you keep adding them. I am the largest single digit. What am I?
9
Any multiple of 9 has a digital root of 9 (for example, 9 x 7 = 63, and 6 + 3 = 9).
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Easy. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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