Lê Quốc Trần Anh Coordinator
16/03/2018 at 11:26-
Tell these number to find is x
=> 100 < x < 1000
=> x has 3 digits.
The hundred-digit has 3 choice
The ten-digit has 3 choice
The units-digit has 3 choice too
So there are 3.3.3 = 27 intergers satisfy
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