future mathletes

# 34 Hard Math Riddles (With Answers) For Future Geniuses

Stump the mathletes of the family with these extra-tricky math riddles and puzzles. BDG; Getty

No one’s indifferent to the long-form math word problem with the opening lines, “There are 67 people on a train traveling west at 45 miles an hour.” Those verbal equations tend to either thrill us or fill us with dread. While we all tumble effortlessly through daily encounters with simple arithmetic, sometimes math riddles and word problems stop us in our tracks. They’re often a thorny and delightful combination of the abstract and the real world, which is why they’re perfect for kids.

To solve a math riddle, kids must convert a few sentences about a real-life scenario into the right combination of mathematical equations. Using logic, creative problem solving, and common sense, children can crack any code, including math riddles. Although tough, the harder ones especially offer a gratifying challenge to kids (and, let’s be frank, adults).

The great news is that shrouding a difficult equation behind a fun and engaging riddle is the best way to get your kid interested in math well before they face the great divide in eighth grade caused by the quadratic formula. These tricky math riddles keep kids entertained while quietly sharpening their logic and math skills. Odds are, you’ll learn something, too.

1. Riddle: If there are four apples and you take away three, how many do you have? / Answer: You took three apples, so you have three!
2. Riddle: A 300 ft. train is traveling 300 ft. per minute must travel through a 300 ft. long tunnel. How long will it take the train to travel through the tunnel? / Answer: Two minutes. It takes the front of the train one minute, and the rest of the train will take two minutes to clear the tunnel.
3. Riddle: A cellphone and a phone case cost \$110 in total. The cell phone costs \$100 more than the phone case. How much was the cellphone? / Answer: \$105 (not \$110)
4. Riddle: Robert and David played several golf matches against each other in a week. They played for a pizza at each match, but no pizzas were purchased until the end of the week. If Robert and David had the same number of wins at any time, those pizzas were canceled. Robert won four matches (but no pizzas), and David won three pizzas. How many rounds of golf were played? / Answer: 11 / Explanation: David won seven matches — four to cancel out Robert’s four wins and three more to win the pizzas.
5. Riddle: 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? / Answer: 141
6. Riddle: I add five to nine and get two. The answer is correct, but how? / Answer: When it is 9 a.m., add five hours to it, and you will get to 2 p.m.
7. Riddle: There are 100 pairs of dogs in a zoo; a pair of babies are born for each dog. Unfortunately, 23 of the dogs have not survived. How many dogs are left in total? / Answer: 977 dogs / Explanation: 100 x 2 = 200; 200 + 800 = 1,000; 1,000 – 23 = 977
8. Riddle: A group of students were standing in the blazing sun facing due west on a march past event. The leader shouted at them: Right turn! About turn! Left turn! At the end of these commands, which direction are the students facing now? / Answer: East / Explanation: They will turn 90 degrees in a right turn and then 180 degrees in an about-turn, and finally turn 90 degrees in a left turn. Therefore, the students are now facing east.
9. Riddle: A half is a third of it. What is it? / Answer: 1 1/2
10. Riddle: 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? / Answer: 11 cartons / Explanation: Four small boxes (410 = 40 boxes) + seven large boxes (78 = 56 boxes). So, 96 boxes and 11 total cartons.
11. Riddle: When Miguel was 6 years old, his little sister, Leila, was half his age. If Miguel is 40 years old today, how old is Leila? / Answer: She is 37 years old.
12. Riddle: You are given three positive numbers. You can add these numbers and multiply them together. The result you get will be the same. What are the numbers? / Answer: One, two, and three.
13. Riddle: If a hen and a half lay an egg and a half in a day and a half, how many eggs will half a dozen hens lay in half a dozen days? / Answer: Two dozen
14. Riddle: What can you put between a seven and an eight so that the result is greater than a seven but less than an eight? / Answer: A decimal because 7.8 is greater than seven but less than eight.
15. Riddle: Tom was asked to paint numbers outside 100 apartments, which means he will have to paint numbers one through 100. How many times will he have to paint the number eight? / Answer: 20 times / Explanation: (8, 18, 28, 38, 48, 58, 68, 78, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 98)
16. Riddle: What’s the maximum number of times you can subtract five from 25? / Answer: Only once. This is because when you subtract five the first time, 25 becomes 20, then 15, and so on.
17. Riddle: Which weighs more, 16 ounces of soda or a pound of solid gold? / Answer: Neither. They both weigh the same!
18. Riddle: Leon works at the aquarium. When he tries to put each turtle in its own tank, he has one turtle too many. But if he puts two turtles per tank, he has one tank too many. How many turtles and how many tanks does Leon have? / Answer: He has three tanks and four turtles.
19. Riddle: The total cost of a pair of shoes and a hoodie is \$150. The hoodie cost \$100 more than the pair of shoes. How much does each item cost? / Answer: The hoodie costs \$125, and the shoes cost \$25.
20. Riddle: You have two U.S. coins with a total value of 30 cents. One of them is not a nickel. What are the two coins? / Answer: One is a quarter, and one is a nickel.
21. Riddle: Eggs are 12 cents a dozen. How many eggs can you get for a dollar? / Answer: 100 eggs for a penny each
22. Riddle: A duck was given \$9, a spider was given \$36, and a bee was given \$27. Based on this information, how much money would be given to a cat? / Answer: \$18 (\$4.50 per leg)
23. Riddle: “How much is this bag of potatoes?” asked the man. “Thirty-two pounds divided by half of its own weight,” said the grocer. How much did the potatoes weigh? / Answer: 8 lbs
24. Riddle: I am a three-digit number. My tens digit is six more than my ones digit. My hundreds digit is eight less than my tens digit. What number am I? / Answer: 193
25. Riddle: A man is twice as old as his little sister. He is also half as old as his dad. Over a period of 50 years, his sister’s age will become half of their dad’s age. What is the age of the man now? / Answer: 50 years old
26. Riddle: How can you add eight fours together so the total adds up to 500? / Answer: 444 + 44 + 4 + 4 + 4 = 500
27. Riddle: If seven people meet each other and each shake hands only once with each of the others, how many handshakes happened? / Answer: 21
28. Riddle: If four men can build four tables in four hours, how many can eight men build in eight hours? / Answer: 16 tables
29. Riddle: When Lisa was 6 years old, her sister Lucy was half her age. If Lisa is 40 years old today, how old is Lucy? / Answer: 37 / Explanation: Lucy is three years younger than Lisa.
30. Riddle: If you buy a rooster to lay eggs and you expect to get three eggs each day for breakfast, how many eggs will you have after three weeks? / Answer: None. Roosters don’t lay eggs.
31. Riddle: A farmer has 19 sheep on his land. One day, a big storm hits, and all but seven run away. How many sheep does the farmer have left? / Answer: Seven. All but seven ran away.
32. Riddle: 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? / Answer: Three tickets / Explanation: The grandmother is also a mother, and the mother is also a daughter.
33. Riddle: There is a clothing store in Dallas. The owner has made 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? / Answer: \$45 / Explanation: The pricing method consists of charging \$5 for each letter required to spell the item.
34. Riddle: If you go to the movies and you’re paying, is it cheaper to take one friend to the movies twice or two friends to the movies at the same time? / Answer: It’s cheaper to take two friends at the same time. / Explanation: In this case, you would only be buying three tickets, whereas if you take the same friend twice, you are purchasing four tickets.

Editor’s note: All of these mind-boggling math riddles are in the public domain. However, we spotted a few of these on Kids Math Games Online, Get Riddles, Riddles.com, Everything Mom, Mash Up Math, and Greeting Card Poet, which we can’t recommend strongly enough.