Number Riddles With Answers
Updated · Best Riddles With Answers editorial team
Quick answer: This page has 42 number riddles with answers, covering number patterns, mystery numbers, digit puzzles and sequences. It suits students, puzzle fans and parents who want a number game for the car or the classroom. Each answer includes a short line of working so you can check how the number was found. Start with the easy riddles and build up.
Easy Number Riddles
I am the number of days in February in a leap year. What number am I?
29.
I am the smallest number with three digits. What number am I?
100.
I am an even number, and I am the number of legs on an octopus. What number am I?
8.
I am a pair of pairs. What number am I?
4, because 2 + 2 = 4.
I am the number of fingers on one hand, and I sit between 4 and 6. What number am I?
5.
I am the number of cents in a dime. What number am I?
10.
What number comes next: 2, 4, 6, 8, ...?
10, because the numbers go up by 2.
What number comes next: 5, 10, 15, 20, ...?
25, because the numbers go up by 5.
What number comes next: 1, 3, 5, 7, ...?
9, because these are odd numbers going up by 2.
I am neither positive nor negative, and adding me changes nothing. What number am I?
Zero.
I have two digits, both the same, and they add up to 10. What number am I?
55, because 5 + 5 = 10.
I am the largest number you can write with a single digit. What number am I?
9.
Trickier Number Riddles
What number comes next: 1, 8, 27, 64, ...?
125, because these are cube numbers and 5 x 5 x 5 = 125.
What number comes next: 1, 1, 2, 3, 5, 8, 13, ...?
21, because each number is the sum of the previous two: 8 + 13 = 21.
What number comes next: 3, 6, 12, 24, ...?
48, because each number doubles: 24 x 2 = 48.
What is the biggest three-digit number in which every digit is different?
987.
Which number has its letters in alphabetical order when you spell it out?
Forty: F, O, R, T, Y.
I am a two-digit number whose digits add to 9. Reverse my digits and the new number is 27 more than me. What am I?
36. The digits add to 9 and 63 - 36 = 27.
Multiply me by myself and you get 144. What positive number am I?
12, because 12 x 12 = 144.
I am a three-digit number between 150 and 160 that reads the same forwards and backwards. What am I?
151.
How many zeros are there in one million?
6, because 1,000,000 has six zeros.
How many times does the digit 9 appear when you write every number from 1 to 100?
20. It is the units digit in 10 numbers (9, 19 ... 99) and the tens digit in 10 numbers (90 to 99).
I am the only even prime number. What number am I?
2.
Hard Number Riddles
What number comes next: 2, 3, 5, 7, 11, 13, ...?
17, because these are the prime numbers.
What number comes next: 2, 5, 11, 23, ...?
47. Each number is double the last plus 1: 23 x 2 + 1 = 47.
What number comes next: 31, 28, 31, 30, 31, 30, 31, 31, ...?
30. These are the days in January to August, so September has 30.
What number comes next: 3, 3, 5, 4, 4, 3, 5, 5, 4, ...?
3. These count the letters in one, two, three ... nine, and ten has 3 letters.
My three digits add up to 12. My hundreds digit is twice my units digit, and my tens digit is three times my units digit. What number am I?
462. Units 2, hundreds 4, tens 6, and 4 + 6 + 2 = 12.
Five consecutive odd numbers add up to 85. What is the smallest?
13. The middle number is 85 / 5 = 17, giving 13, 15, 17, 19, 21.
What is the smallest number above 1 that leaves a remainder of 1 when divided by 2, 3, 4, 5 and 6?
61. The smallest number that 2 to 6 all divide into is 60, and 60 + 1 = 61.
How many two-digit numbers have digits that add up to 10?
9: 19, 28, 37, 46, 55, 64, 73, 82 and 91.
What is the smallest number with exactly six factors?
12, whose factors are 1, 2, 3, 4, 6 and 12.
How many squares of any size are hidden in a 3 by 3 grid of small squares?
14. There are 9 small ones, 4 two-by-two squares and 1 big one: 9 + 4 + 1 = 14.
Quick-Fire Number Riddles
The number of lives a cat is said to have.
Nine.
The number of colours in a rainbow.
Seven.
The number the Roman numeral C stands for.
One hundred.
A thousand thousands.
A million.
The number of wheels on a tricycle.
Three.
Half a dozen.
Six.
The number of years in a decade.
Ten.
One more than a dozen, said to be unlucky.
Thirteen.
How to Use These Riddles
For sequence riddles, look at the gaps between numbers first. If the gaps are equal, the rule is addition. If the gaps themselves grow, look at the gaps of the gaps. If each number is a multiple of the last, the rule is multiplication.
For mystery number riddles, write down what you know about the digits and try the clues one at a time. Checking your final number against every clue is the best way to be sure of an answer.
Frequently Asked Questions
What is the next number in the Fibonacci sequence 1, 1, 2, 3, 5, 8, 13?
The next number is 21. In the Fibonacci sequence each number is the sum of the two before it, so 8 + 13 = 21. After that comes 34, then 55.
Which number has its letters in alphabetical order?
Forty. Spelled F, O, R, T, Y, its letters are in alphabetical order, and no other number name in English has this property. It makes a good puzzle for wordplay fans.
How do I solve a number sequence riddle?
Check the differences between neighbouring numbers first, then ratios, then look for special families like squares, primes or Fibonacci numbers. Test your rule on every term before trusting it.
Are these number riddles suitable for children?
Yes. The easy section uses small numbers and simple patterns, while the later sections add digit puzzles and harder sequences that suit older children, teenagers and adults.
