What number is twice the sum of it’s digits?

Answer: 18 (1+8=9)

More Math Riddles with answers

More Math Riddles

What odd number becomes even when beheaded?
What single-digit number should go in the box with the question? 6 5 9 2 7 1 4 3 5 ? 8 0 2 8 1
When I was 10, Mary was half my age. Now I'm 50, how old is Mary?
When my father was 31 I was 8. Now he is twice as old as me. How old am I?
When my father was 31 I was 8. Now he is twice as old as me. How old am I?
Where can you place one line to make the following true, 5+5+5=550?
Why is it easier to count cows than sheep?
Why should you never mention the number 288 in front of anyone?
Why was the math book always so depressed?
You go to the doctor because you're ill and he prescribes you with 3 pills and tells you to take them every half hour. How long do the pills last you?
You have 14 brown socks, 14 blue socks and 14 black socks in your sock drawer. How many socks must you remove (without looking to be sure) to have a matched pair?
You have 14 brown socks, 14 blue socks and 14 black socks in your sock drawer. How many socks must you remove (without looking to be sure) to have a matched pair?