If you write down all the whole numbers from 1 to 100 inclusive, how many times will you write the digit '7'?
20 times
The digit 7 appears in the units place 10 times (7, 17, 27, ..., 97) and in the tens place 10 times (70, 71, 72, ..., 79). 10 + 10 = 20.
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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