Math Riddles for Kids: 40 Number Puzzles With Answers

Good math riddles for kids are short number puzzles with one clear answer that a child can reason out in a minute or two. Here are 40 original math riddles with answers, sorted by age, each with a one-line explanation.

Use them as a warm-up, a car game or a brain break. When children want more practice with the same skills, our free math learning games cover number bonds, times tables, place value and fractions, with no sign-up.

How to use these math riddles for kids

Read each riddle aloud twice, then wait. Ask “How do you know?” before saying whether an answer is right. The “I am a number” riddles use whole numbers, and every one of these math riddles with answers was checked by a short computer search: exactly one answer fits all the clues.

Ages are a guide. Confident younger children often enjoy the harder number riddles for kids, and older ones like an easy set for speed.

Number riddles for kids aged 5 to 7: counting and doubles

These easy riddles use counting, doubles and adding or taking away within 20. Let children use fingers, cubes or a printable number line.

1. I am bigger than 5 and smaller than 7. What number am I?
   Answer: 6. It is the only whole number between 5 and 7.
2. Add me to myself and you get 8. What number am I?
   Answer: 4. 4 + 4 = 8, a doubles fact.
3. I am an odd number between 6 and 10, and I am not 7. What am I?
   Answer: 9. The odd numbers between 6 and 10 are 7 and 9.
4. A spider has 8 legs. Two spiders are hiding under the bed. How many spider legs are there?
   Answer: 16. 8 + 8 = 16.
5. Start at 7 and count on 3 more. Where do you stop?
   Answer: 10. 7, then 8, 9, 10.
6. I come straight after 19 when you count. What number am I?
   Answer: 20. 19 + 1 = 20.
7. Take me away from 10 and 6 is left. What number am I?
   Answer: 4. 10 − 4 = 6.
8. How many fingers are there on 3 hands?
   Answer: 15. 5 + 5 + 5 = 15.
9. I am an even number between 11 and 15, and I am not 12. What am I?
   Answer: 14. The even numbers between 11 and 15 are 12 and 14.
10. Sam has 3 red balloons and 4 blue balloons. Two blue balloons pop. How many balloons are left?
    Answer: 5. 3 + 4 = 7, then 7 − 2 = 5.

Riddles for ages 7 to 9: place value and times tables

These math riddles for kids practice place value, halving and times tables. Riddle 12 is a skip-counting puzzle; our guide to skip counting for kids makes a good warm-up.

11. I am a two-digit number. My tens digit is 4, and my ones digit is 3 more than my tens digit. What am I?
    Answer: 47. Tens digit 4, ones digit 4 + 3 = 7.
12. Count in fives starting at 5: 5, 10, 15 and so on. Which number do you say seventh?
    Answer: 35. 5, 10, 15, 20, 25, 30, 35.
13. I am a two-digit number. My digits add up to 9, and my tens digit is double my ones digit. What am I?
    Answer: 63. 6 is double 3, and 6 + 3 = 9.
14. Half of me is 25. What number am I?
    Answer: 50. 25 + 25 = 50.
15. I am between 30 and 40. I am in the 3 times table and the 4 times table. What am I?
    Answer: 36. 32 is only a 4s fact and 33 and 39 are only 3s facts.
16. I am an even number between 20 and 30. My digits add up to 10. What am I?
    Answer: 28. 2 + 8 = 10; 22, 24 and 26 add up to less.
17. Pencils come in packs of 10. Ali buys 4 packs and gives 6 pencils away. How many does he keep?
    Answer: 34. 4 × 10 = 40, then 40 − 6 = 34.
18. I have three digits. My hundreds digit is 1, my tens digit is 0, and my ones digit is the number of sides on a triangle. What am I?
    Answer: 103. 1 hundred, 0 tens and 3 ones.
19. Double 15, then take away 5. What do you get?
    Answer: 25. 15 × 2 = 30, and 30 − 5 = 25.
20. I am a two-digit number. Swap my digits and you get a number 9 bigger than me. My digits add up to 7. What am I?
    Answer: 34. 43 − 34 = 9 and 3 + 4 = 7.

Harder puzzles for ages 9 to 11: remainders and primes

These harder riddles bring in remainders, square and prime numbers and fractions of amounts. Keep a multiplication chart nearby so the puzzle is about reasoning, not recall.

21. I am between 50 and 80. Divide me by 5 and the remainder is 4. Divide me by 6 and the remainder is 5. What am I?
    Answer: 59. 59 = 5 × 11 + 4 = 6 × 9 + 5.
22. I am a square number between 40 and 60. What am I?
    Answer: 49. 7 × 7 = 49; 36 and 64 are outside.
23. I am a prime number between 20 and 30, and my digits add up to 11. What am I?
    Answer: 29. The primes are 23 and 29; only 2 + 9 = 11.
24. I am a two-digit number. My digits multiply to 24 and add up to 10. My tens digit is the smaller one. What am I?
    Answer: 46. 4 × 6 = 24 and 4 + 6 = 10.
25. Three quarters of me is 24. What number am I?
    Answer: 32. One quarter is 24 ÷ 3 = 8, so the whole is 8 × 4 = 32.
26. A farmer counts 12 heads and 34 legs among his chickens and goats. How many goats are there?
    Answer: 5. 12 chickens would have 24 legs; each goat adds 2 more, and 10 ÷ 2 = 5.
27. What is the smallest number that 2, 3, 4 and 5 all divide into exactly?
    Answer: 60. 3 × 4 × 5 = 60, and 2 already divides 4.
28. Three numbers in a row add up to 48. What is the largest of them?
    Answer: 17. 15 + 16 + 17 = 48.
29. I am an even multiple of 9 between 100 and 120. What am I?
    Answer: 108. The choices are 108 and 117; only 108 is even.
30. A book has pages numbered 1 to 50. How many times is the digit 3 printed?
    Answer: 15. Five times as a ones digit (3, 13, 23, 33, 43) and ten times in 30 to 39.

Challenge riddles for ages 11 and up

The last ten riddles need a little algebra, logic or careful counting. Encourage children to write a number sentence before they guess.

31. Two numbers add up to 30, and their difference is 8. What are the numbers?
    Answer: 19 and 11. 19 + 11 = 30 and 19 − 11 = 8.
32. I am a two-digit number equal to 4 times the sum of my digits. My ones digit is 3 more than my tens digit. What am I?
    Answer: 36. 3 + 6 = 9, and 4 × 9 = 36.
33. I multiply a number by 3 and then add 7. The answer is 40. What was my number?
    Answer: 11. Work backwards: 40 − 7 = 33, and 33 ÷ 3 = 11.
34. What is the smallest number greater than 1 that leaves a remainder of 1 when divided by 2, 3, 4, 5 or 6?
    Answer: 61. 60 divides exactly by all five, so 60 + 1 = 61.
35. An adult ticket costs twice as much as a child ticket. Two adult tickets and three child tickets cost 35 coins. How much is a child ticket?
    Answer: 5 coins. Two adults cost the same as four children, so 7 child tickets cost 35.
36. I am a three-digit number that reads the same backwards. My digits add up to 13, and I am a multiple of 5. What am I?
    Answer: 535. I must start and end with 5, so the middle digit is 13 − 10 = 3.
37. The mean of four numbers is 9. Three of them are 6, 8 and 10. What is the fourth?
    Answer: 12. The total must be 4 × 9 = 36, and 36 − 24 = 12.
38. Use each of the digits 1, 2, 3 and 4 once to make the largest possible even number. What is it?
    Answer: 4312. End in 2 so that 4, 3 and 1 can go in front.
39. I am a fraction equal to 2/3. My numerator and denominator add up to 15. What fraction am I?
    Answer: 6/9. 6/9 simplifies to 2/3 and 6 + 9 = 15.
40. How many squares of any size can you find on a 3 by 3 grid?
    Answer: 14. Nine 1 by 1, four 2 by 2 and one 3 by 3.

How we checked that each riddle has only one answer

Every riddle was run through a short program that lists the numbers allowed by the first clue and then removes any that break a later clue. This table shows the idea for the eight riddles with several clues. The first clue alone leaves a handful of numbers, and the full set leaves exactly one:

For riddle 21 only 59 survives, out of 29 numbers between 51 and 79, and riddle 34 has no other answer below 61 (the next one is 121). You can use the same method with children: list the numbers that fit the first clue, then cross out any that break the second.

It is a good habit for solving number riddles for kids at any age, and it shows why a riddle with one clue rarely has a single answer. When your child writes their own riddle, ask them to run this check before they swap it with a friend.

Four ways to use riddles in class

Math riddles for kids work best as a short, regular routine. Here are four that fit around a normal lesson.

1. Riddle of the day

Write one riddle on the board before the lesson. Students solve it on mini whiteboards, then two children explain different methods.

2. Think, pair, share

Give one harder riddle. Students think alone for a minute, compare with a partner, then share. Riddles 21 to 40 suit this, as most have more than one route to the answer.

3. Write your own riddle

Students write a riddle with exactly one answer and swap. Checking that no second number fits is real reasoning. A starter frame: “I am between __ and __. I am in the __ times table.”

4. Exit-ticket riddle

End with a riddle that uses the day’s skill. Students hand in the answer plus one sentence of reasoning, giving you a quick check of who understood.

Story riddles such as 10, 17 and 26 lead neatly into our math word problems worksheets, which use the same read, picture, calculate and check habit.

Common mistakes when solving math riddles for kids

• Stopping at the first fit. Most number riddles for kids have several clues. In riddle 15, 32 is in the 4 times table but not the 3 times table. Check every clue.
• Misreading “between”. Between 20 and 30 does not include 20 or 30.
• Mixing up digits and numbers. “My digits add up to 10” means 2 + 8 for 28.
• Guessing instead of listing. For riddles 21 and 36, list the possible numbers and cross them out.
• Not working backwards. When a riddle gives the result (7, 25, 33), undo each step in reverse.

Where math riddles fit in the curriculum

Math riddles for kids practice skills that are on the curriculum. The Common Core State Standards for Mathematics put skip counting by 5s in 2nd grade (2.NBT.2) and prime and composite numbers in 4th grade (4.OA.4).

The national curriculum in England has Year 1 students count in twos, fives and tens, and Year 5 students use prime and square numbers. For more free problem solving, try NRICH from the University of Cambridge.

More number puzzles and practice on PrintSheetLab

Math riddles for kids build reasoning and games build speed, so pair them. After the 7 to 9 set, try the Make 100 game; after the times-table riddles, play the mixed times tables game. The math worksheet generator makes printable practice with answer keys.

Related guides and printables

• Free online math games for kids, sorted by grade
• Times tables tricks for riddles 15, 29 and 34
• Printable puzzles for kids, including logic puzzles
• Even or odd game for young riddle solvers
• How to improve concentration in kids with short tasks

Sources

Grade references: Common Core State Standards for Mathematics (2.NBT.2, 4.OA.4) and the Department for Education’s mathematics programmes of study for key stages 1 and 2. All 40 riddles were written for PrintSheetLab and checked for a single answer by computer.

Frequently asked questions

7 quick answers

What are some easy math riddles for kids?

Try “Add me to myself and you get 8” (answer 4) or “I come straight after 19” (answer 20). Riddles 1 to 10 suit ages 5 to 7.

How do math riddles for kids help learning?

They make children read carefully, list possibilities and test every clue. Explaining an answer aloud builds math vocabulary.

What is a good math riddle for a 10-year-old?

Riddle 23: “I am a prime number between 20 and 30, and my digits add up to 11.” The answer is 29.

How can I write my own math riddles for kids?

Pick a number and write two or three clues. List every number that fits; if more than one does, add a clue.

What if my child finds a different answer?

Check it against every clue. Each riddle here has exactly one answer, so a different number breaks at least one clue.

Where can I find 2nd grade math riddles?

Riddles 11 to 20 suit 2nd and 3rd grade. These 2nd grade math riddles cover place value, halving and skip counting.

How do I know a math riddle has only one answer?

List every number that fits the first clue, then cross out the ones that break the next clues. In riddle 21 that leaves 59 out of 29 possible numbers, and in riddle 15 it leaves 36 out of 9.