I am a two-digit prime number. If you reverse my digits, the new number is also prime, and the difference between us is 18. What number am I?
13
The pairs of two-digit numbers with a difference of 18 whose digits are reversals include 13 and 31. Both 13 and 31 are prime numbers.
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: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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