Math Riddles

A collection of Math Riddles for fun and pleasure! Tease your brain with these riddles, then click to show or hide the answer. (Note: You may need to enable JavaScript on your browser for the answers to show properly.)

Also visit our Math Trivia page for more arithmetic riddles, algebra riddles, geometry riddles, statistics riddles etc.

1. Why should you never mention the number 288 in front of anyone? Because it is too gross (2 x 144 - two gross).


2. Which weighs more?  A pound of iron or a pound of feathers? Both weigh the same.


3. How is the moon like a dollar? They both have 4 quarters.


4. What is alive and has only 1 foot? A leg.


5. When do giraffes have 8 feet? When there are two of them.


6. How many eggs can you put in an empty basket? Only one, after that the basket is not empty.


7. What coin doubles in value when half is deducted? A half dollar.


8. What is the difference between a new penny and an old quarter? 24 cents.


9. If you can buy eight eggs for 26 cents, how many can you buy for a cent and a quarter? 8.


10. Where can you buy a ruler that is 3 feet long? At a yard sale.

11. If there were 9 cats on a bridge and one jumped over the edge, how many would be left? None - they are copycats.


12. If you take three apples from five apples, how many do you have? You have three apples.


13. What has 4 legs and only 1 foot? A bed.


14. How many times can you subtract 6 from 30? Once; after that it is no longer 30 (Don't try this in a test!)


15. If one nickel is worth five cents, how much is half of one half of a nickel worth? $0.0125


16. How many 9's between 1 and 100? 20.


17. Which is more valuable - one pound of $10 gold coins or half a pound of $20 gold coins? It is the same. One pound is twice of half pound.


18. It happens once in a minute, twice in a week, and once in a year. What is it? The letter 'e'.


19. How can half of 12 be 7? Cut XII into two halves horizontally. You get VII on the top half.


20. When things go wrong, what can you always count on? Your fingers.



21. Which month has 28 days? All of them.


22. What’s the easiest way to double your money? Put it in front of a mirror.


23. What occurs twice in a week, once in a year but never in a day? The letter e


24. Where do fish keep their money? In the river bank


25. Why is the longest human nose on record only 11 inches long? Otherwise it would be a foot.


26. Why are diapers like 100 dollar bills? They need to be changed.


27. A street that is 40 yards long has a tree every 10 yards on both sides. How many trees are there on the entire street? 10, 5 on each side.


28. What goes up and never comes down? Your age.


29. What did one math book say to the other math book? Wow, have I got problems!


30. I am an odd number; take away a letter and I become even. What number am I? SEVEN take away S becomes EVEN



31. As I was going to St. Ives
    I met a man with seven wives.
    Each wife had seven sacks,
    Each sack had seven cats,
    Each cat had seven kits;
    Kits, cats, sacks and wives,
    How many were going to St. Ives? One (the narrator)



32. You want to cross a bridge to get to the other side of the crevice, but there's a problem. The bridge, which takes an hour to walk across, is guarded in the middle by a guard who wakes up every half hour and carries back anybody crossing the bridge back to where he or she came from. How long does it take for me to get to the other side? One hour. You walk across the bridge as you normally would, and after half an hour, you've reached the middle of the bridge, and the guard wakes up. Right before he wakes up, turn around and face the other direction so that the guard will think that you were heading the opposite direction. The guard will automatically carry you back to the side where he thought you came from, which is the side you wanted to go to.




33. What are the 10 types of people in the world? Those who understand binary and those who don't


34. Why didn't the quarter roll down the hill with the nickel? Because it had more cents.


35. What happened to the plant in math class? It grew square roots.


36. Why did the chicken cross the mobius strip? To get to the same side.


37. Why did I divide sin by tan? Just cos.


38. Where do math teachers go on vacation? To Times Square.


39. What do you call a number that can't keep still? A roamin' numeral.


40. Why did the mutually exclusive events break up? They had nothing in common.


41. How does a mathematician induce good behavior in her children? I've told you n times, I've told you n+1 times.


42. How do you know when you've reached your Math Professors voice-mail? The message is 'The number you have dialed is imaginary. Please, rotate your phone by 90 degrees and try again...'



43. Why did the 30-60-90 triangle marry the 45-45-90 triangle? They were right for each other.


44. Why didn't the Romans find algebra very challenging? Because X was always 10.


45. Why couldn't the angle get a loan? His parents wouldn't Cosine.


46. What do you call an angle that is adorable? acute angle


47. What do you call a destroyed angle? A Rect-angle


48. Why did the student get upset when his teacher called him average? It was a 'mean' thing to say!


49. Why does nobody talk to circles? Because there is no point!


50. Which triangles are the coldest? Ice-sosceles triangles


51. What do you call a dead parrot? Polygon


52. What's the difference between a diameter and a radius? A Radius


53. How do deaf mathematicians communicate? They use sine language


54. What do organic mathematicians throw into their fireplaces? Natural Logs


55. Why shouldn't you argue with a decimal? Decimals always have a point.


56. How many mathematicians does it take to change a light bulb? One: he gives it to three physicists, thus reducing it to a problem that has already been solved.


57. Why did the chicken cross the road? The answer is trivial and is left as an exercise for the reader.


58. What did the circle say to the tangent line? Stop touching me.


59. Why do mathematicians like parks? Because of all the natural logs.


60. What kind of tree could a math teacher climb? Geometry

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