# Math Riddles

Test your knowledge with these math riddles.

Kids’ author Michael O’Halloran shares some of his favorite math riddles.

For those in a hurry or who want a quick flavor of the types of riddles, here are three examples.

- A cell phone and phone case cost $110 in total. The cell phone costs $100 more than the phone case. How much was the cell phone?
**$105.** - If there are four apples and you take away three, how many do you have?
**Three apples.** - A duck was given $9. A spider was given $36. A bee was given $27. Based on this information, how much money would be given to a cat?
**$18 ($4.50 per leg).**

## Math Riddles for Kids

Here we go.

1.) If two’s company and three’s a crowd, what are four and five?**Nine.**

2.) If you multiply this number by any other number, the answer will always be the same. What number is this?**Zero.**

3.) A duck was given $9. A spider was given $36. A bee was given $27. Based on this information, how much money would be given to a cat?**$18 ($4.50 per leg).**

4.) A grandfather, two fathers, and two sons went to the movie theater together, and everyone bought one movie ticket each. How many tickets did they buy in total?**Three (the grandfather is also a father, and the father is also a son).**

See 65 good brainteasers for teens.

5.) A little boy goes shopping and purchases 12 tomatoes. On the way home, all but nine get mushed and ruined. How many tomatoes are left in good condition?**Nine tomatoes.**

See Hardest Riddles of All Time.

## Math Riddles For Middle Schoolers

We’re raising the ante. Put on your thinking caps for a logic puzzle direction that incorporates math.

6.) What occurs twice in a week, once in a year, but never in a day?**The letter E.**

See Fun Scavenger Hunt Riddles.

7.) If there are four apples and you take away three, how many do you have?**Three apples.**

8.) If the zookeeper had 100 pairs of animals in her zoo and two pairs of babies are born for each original animal, then sadly, 23 animals don’t survive. How many animals do you have left in total?**977 animals (100×2 = 200; 200+800 = 1000; 1000-23 = 977).**

9.) Zoey has a very big family. She has 20 aunts, 20 uncles and 50 cousins. Each of her cousins has an aunt who is not Zoey’s aunt. How is this possible? **Their aunt is Zoey’s mom!**

10.) When Harry was six years old, his little sister Mary was half his age. How old will Mary be when Harry is forty years old? **She will be thirty-seven years old.**

### Tricky Math Riddles and Brain Games

11.) Eggs are $0.12 a dozen. How many eggs can you get for a dollar?**One hundred eggs (one penny each).**

12.) In an alien land far away, half of 10 is 6. If the same proportion holds, then what is 1/6th of 30 in this alien land?**6.**

13.) Scott has $28.75. He purchased three cookies that cost $1.50 each, five newspapers that each cost $0.50, five flowers for $1.25 each, and used the remainder of the cash on a pair of sunglasses. How much were the sunglasses?**$15.50.**

## Easy Puzzles

14.) Which month has 28 days?**All of them, of course!**

15.) What four days of the week start with the letter T?**Tuesday, Thursday, Today, and Tomorrow.**

16.) What goes up and doesn’t come back down?**Your age.**

17.) A cell phone and phone case cost $110 in total. The cell phone costs $100 more than the phone case. How much was the cell phone?**$105.**

18.) What has a thumb and four fingers but is not alive?**A glove.**

19.) What occurs once every minute, twice in every moment, and yet never in a thousand years?**The letter M.**

### Number Math Riddles

20.) I am an odd number; take away an alphabet, and I become even. What number am I?**Seven (SEVEN-S=EVEN).**

21.) Using only addition, how can you add eight 8’s to get the number 1,000?**888 +88 +8 +8 +8 =1,000.**

22.) How did the soccer fan know before the game that the score would be 0-0?**The score is always 0-0 before the game.**

23.) I add five to nine and get two. The answer is correct, but how?**When it is 9 am, add 5 hours to it, and you will get 2 pm.**

24.) The ages of a father and son add up to 66. The father’s age is the son’s age reversed. How old could they be?**Three possible answers: the father-son duo could be 51 and 15 years old, 42 and 24 years old, or 60 and 06 years old.**

25.) A merchant can place eight large boxes or 10 small boxes into a carton for shipping. In one shipment, the shipper sent a total of 96 boxes. If there are more large boxes than small boxes, how many cartons did the shipper ship?**11 cartons total. Seven large boxes (7 x 8 = 56 boxes) and four small boxes (4 x 10 = 40).**

26.) My sister lives at the reverse of my house number. The difference between our house numbers ends in two. What are the lowest possible numbers for our house?**19 and 91.**

## Fun Math Riddles

27.) Where do fish keep their money?**In the river bank.**

28.) If you buy a rooster to lay eggs and expect to get three eggs each day for breakfast, how many eggs will you have after three weeks?**None, roosters do not lay eggs.**

29.) I am an odd number. Take away a letter, and I become even. What number am I?**Seven.**

30.) I am a place, in a state. I am an answer to a math problem. The math problem is: To get a cube, you multiply something by 6. What do you multiply by?**You Times Square!**

31.) What weighs more, a pound of iron or a pound of feathers?**Both would weigh the same.**

32.) When asked how old she was, Janey replied, “In two years, I will be twice as old as I was five years ago.” How old is she?**She’s 12.**

33.) Name the favorite dessert of a math teacher. **Pi(e)**

## Puzzles

Ready for some serious problem-solving?

34.) How can you make the following equation true by drawing only one straight line: 5+5+5=550? Can you figure it out?**Draw a line on the first plus sign that turns it into a 4! The equation then becomes true: 545+5=550. You could also change the equal symbol to a crossed-out equal symbol which means “not equal to.”**

35.) A certain number has three digits. The sum of the three digits equals 36 times this number. Seven times the left digit plus 9 equals 5 times the sum of the two other digits. 8 times the second digit minus 9 is equal to the sum of the first and third. What is the number?**324.**

36.) Can you arrange four nines to make it equal to 100?**99+9/9 = 100.**

37.) Caleb is 54 years old, and his father, Franklin is 80. How many years ago was Franklin three times the age of his son Caleb?**41 years ago.**

38.) The day before yesterday, I was 21, and the next year I will be 24. What day is my birthday?**31st December. It must be on the 1st of January when I turned 22 and so 21 the day before. As it is now a new year, I will be 23 this year and 24 next year.**

39.) If it were two hours later, it would be half as long until midnight as it would be if it were an hour later. What time is it now?**9 pm.**

40.) There are several books on a bookshelf. How many books are on the shelf if one book is the 4th from the left and the 6th from the right?**9 books.**

### Good Math Riddles: Easy, Hard, Tricky

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

42.) If two’s company and three’s a crowd, what are four and five?**Four and five = nine.**

43.) Adored by few, Feared and hated by many. Mistress of the entire universal reason, Master in the art of numbers. Some may have solved many of your mysteries, But there are still many of them to find. What are they?**Mathematics.**

44.) Two fathers and two sons go fishing. Each of them catches one fish. So why do they bring home only three fish?**Because the fishing group consists of a grandfather, his son, and his son’s son.**

45.) What has a face and two hands but no arms or legs?**A clock.**

46.) If it took 6 people 9 hours to build a barn, how long would it take 12 people to build the same barn?**None, the barn is already built.**

47.) One brother said of his younger brother, “Two years ago, I was three times as old as my brother. In three years, I will be twice as old as my brother.” How old are each of the brothers now?**The older brother is 17 years old, and the younger brother is 7.**

## Hard Ones

48.) One out of 9 otherwise identical balls is overweight. How can it be identified after 2 weighings?**Weigh a group of 3 balls against another group of 3. Then you’ll know which group of 3 contains the heavy ball.** Pick 2 balls from that group and weigh one against the other.

49.) A nonstop train leaves Moscow for Leningrad at 60 mph. Another nonstop train leaves Leningrad for Moscow at 40 mph. How far apart are the trains 1 hour before they pass each other?**100 miles (60+40).**

50.) I am a three-digit number. My tens digit is five more than my one’s digit. My hundreds digit is eight less than my tens digit. What number am I?**194.**

51.) When my father was 31, I was 8. Now he is twice as old as me. How old am I?**The age difference is 23 years, so I must be 23 if my father is twice as old as me.**

52.) If seven people meet each other and each shakes hands only once, how many handshakes will there have been?**21 (most people would think there were 42 handshakes).**

### Tough Math Riddles

53.) In a pond, there are some flowers with some bees hovering over them. How many flowers and bees are there if both the following statements are true: 1. If each bee lands on a flower, one bee doesn’t get a flower. 2. If two bees share each flower, there is one flower left out.**4 bees and 3 flowers.**

54.) The ages of a father and son add up to 66. The father’s age is the son’s age reversed. How old could they be (there are 3 possible solutions)?**42 and 24. 51 and 15. 60 and 6.**

55.) Janie’s friends were chipping in to buy her a wedding shower present. At first, 10 friends chipped in, but 2 of them dropped out. Each of the 8 had to chip in another dollar to bring the amount back up. How much money did they plan to collect?**$40 (10 at $4, or 8 at $5).**

See Brain Teasers.

### Math Riddles with Answers

56.) There are two ducks in front of two other ducks. And, there are two ducks behind two other ducks. There are two ducks beside two other ducks. How many ducks are there?**4 ducks (in a square).**

57.) I asked a girl how old she was. She said, “In 2 years, I will be twice as old as I was 5 years ago.” How old is she?**12.**

58.) A man dies of old age on his 25th birthday. How is this possible?**He was born on February 29th.**

59.) I am a three-digit number.

My tens digit is five more than my one’s digit.

My hundreds digit is eight less than my tens digit.

What number am I?**Number 194.**

60.) A farmer has 17 sheep, and all but 9 die. How many are left?**Nine.**

61.) What three positive numbers give the same result when multiplied together as when added together?**1, 2, and 3.**

62.) If you can purchase eight eggs for 26 cents, how many can you buy for a cent and a quarter?**Eight.**

63.) Three matches are sitting on a table; without adding another makes for three matches four. You are not allowed to break any of the matches.**Shape the three matches into a Roman numeral four.**

64.) Using only addition, how can you add eight 8s to get the number 1,000?**888 + 88 + 8 + 8 + 8 = 1,000.**

You might like National STEM/STEAM Day.

### Problem-Solving Skills

65.) I am a three-digit number. My second digit is four times bigger than the third digit. My first digit is three less than my second digit. Who am I? **141.**

66.) What can you put between seven and eight so that the answer is greater than seven but less than eight? **A decimal point.**

67.) There is a clothing store in Eagan. The owner has devised his own method of pricing items. A vest costs $20, socks cost $25, a tie costs $15, and a blouse costs $30. Using the method, how much would a pair of underwear cost? **$45. The pricing method charges $5 for each letter required to spell the item.**

68.) When John was six years old, he hammered a nail into his favorite tree to mark his height. Ten years later, at age sixteen, John returned to see how much higher the nail was. If the tree grew by five centimeters each year, how much higher would the nail be? **The nail would be at the same height since trees grow at their tops.**

69.) What does one math textbook say to another? **I have so many problems.**

70.) A dog was tied to a 15-foot rope, but the dog was able to walk 30 feet. How come?**The rope wasn’t tied to anything.**

## Math Brain Teasers

71.) Two schoolgirls were traveling from the city to a summer cottage on an electric train. “I notice,” one of the girls said, “that the trains coming in the opposite direction pass us every 5 minutes. What do you think—how many trains arrive in the city in an hour, given equal speeds in both directions?” “Twelve, of course,” the other girl answered, “because 60 divided by 5 equals 12.” The first girl disagreed. What do you think?

Show Answer:*If the girls had been on a standing train, the first girl’s calculations would have been correct, but their train was moving. It took 5 minutes to meet a second train, but it took the second train 5 more minutes to reach where the girls met the first train. So the time between trains is 10 minutes, not 5, and only 6 trains per hour arrive in the city.*

### Grandmother Riddle

72.) A grandmother, two mothers, and two daughters went to a baseball game together and bought one ticket each. How many tickets did they buy in total?

*Three tickets because the grandmother is also a mother and the mother is also a daughter!*

### The Snail Problem

73.) A snail is at the bottom of a 20-meter-deep pit. Every day, the snail climbs 5 meters upwards, but at night, it slides 4 meters back downwards. How many days does it take before the snail reaches the top of the pit?*The snail reaches the top of the pit on the 16th day. On the first day, the snail reaches a height of 5 meters, slides down 4 meters at night, and thus ends at a* height of 1 meter. And on the second day, he reaches 6 meters but slides back to 2 meters.

On the third day, he reaches 7 meters but slides back to 3 meters. And* on the fifteenth day, he reaches 19 meters but slides back to 15 meters. On the sixteenth day, he reached 20 meters, so now he is at the top of the pit.*

### Difficult Math Puzzles Word Problems

74.) There is a certain club which is for men only. Six hundred men belong to this club, and 5% of these men wear one earring. Of the other 95% membership, half wear two earrings, and the other half wear none. How many earrings are being worn in this club?*Six hundred. We know that 5% or 30 of *the *men are wearing one earring. Of the other 95%, or 570, we know that half are wearing two earrings and the other half none. This is the same as if they all wore one.*

75.) At the time of shipping, Tom can place 10 small boxes or eight large boxes into a carton. A total of 96 boxes were sent in one shipment. The number of small boxes was less than the large boxes. What is the total number of cartons he shipped?

*11 cartons Explanation: Four small boxes (410 = 40 boxes) + seven large boxes (78 = 56 boxes). So, 96 boxes and 11 total cartons.*

## Are Math Riddles Just For Nerds?

Heck no! They are for everyone who finds enjoyment in them or is interested in advancing their learning and expanding their minds.

Here are some notables who have taken an interest in math:

- Art Garfunkel
- Sergey Brin (Cofounder of Google)
- Lisa Kudrow
- Cindy Crawford
- Marie Curie
- Huey Lewis
- Danica McKellar (Winnie Cooper in The Wonder Years)

Being able to solve these riddles can help you solve other challenges in your day-to-day life. If anyone makes fun of you for liking math puzzles, those folks likely have a hard time solving the problems independently.

Educators use math story problems to enhance understanding and visualization for their students. These math riddles with answers are a fun way to test your ability to solve math problems.

**By Michael O’Halloran**

*Michael is an author, toy inventor, and publisher of Greeting Card Poet.*

**Etcetera**

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