I am a prime number. If you reverse my digits, I become a composite number whose factors are 3 and 11. What number am I?
64
6 + 4 = 10. Reverse is 46. 64 - 46 = 18.
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: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
More math riddles
In a race of five runners, Bob finished two places ahead of Dan. Charlie finished one place behind Alice. Ed finished two places behind Charlie. If Dan finished last (5th), in which position did Alice finish?
Santa delivers 9 presents on each of 5 streets. How many presents is that?
I am an even two-digit number. Both of my digits are prime numbers, and my digits add up to a square number. What number am I?
Find a number whose double plus its half equals 50.
Ida has 3 gold coins and finds 6 more. How many gold coins does Ida have now?
A lily pad doubles in size every day. On the 30th day, it covers the entire pond. On what day did it cover exactly half of the pond?