Math Riddles

Math riddles are a scary territory to many. Math is already a science of problems, tricky statements, abstract imagination, and heavy thinking, could it also be fun? The answer is yes, and proof can be found ahead. Will the numbers be your friends or your doom? Psst, we’ll give you a hint: if it looks like you have to do a lot of calculations, then the solution might not require calculations at all!

35 Math Riddles With Answers

How many apples grow on an apple tree?

Answer: All of them

If three cats catch three mice in three minutes, how many cats would be needed to catch 100 mice in 100 minutes?

Answer: The same three cats would do. Since these three cats are averaging one mouse per minute, given 100 minutes, the cats could catch 100 mice.

If someone says to you, “I'll bet you $1 that if you give me $2, I will give you $3 in return“, would this be a good bet for you to accept?

Answer: No. This is a situation where you lose even if you win. Assuming the other person is being wise, they would take your $2 and say, “I lose“, and give you $1 in return. You win the bet, but you're out $1

Three people check into a hotel. They pay $30 to the manager and go to their room. The manager suddenly remembers that the room rate is $25 and gives $5 to the bellboy to return to the people. On the way to the room the bellboy reasons that $5 would be difficult to share among three people so he pockets $2 and gives $1 to each person. Now each person paid $10 and got back $1. So they paid $9 each, totalling $27. The bellboy has $2, totalling $29. Where is the missing $1?

Answer: We have to be careful what we are adding together. Originally, they paid $30, they each received back $1, thus they now have only paid $27. Of this $27, $25 went to the manager for the room and $2 went to the bellboy

A certain number has three digits. The sum of the three digits equals 36 times this number. Seven times the left digit plus 9 is equal to 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?

Answer: This one is fairly easy - 324 is the answer

A kind man comes across a dirty box, a voice says to him “Coconuts, $5 a dozen”With his lightning quick arithmetic he calculates that if he sold those same coconuts to the coconut air assault team for the accepted rate of $3 per dozen that in no time at all he would be a millionaire. What's with this guy, assuming his math is accurate?

Answer: He was a billionaire

While on my way to St. Ives, I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kitten, cats, sacks, wives, How many were going to St. Ives?

Answer: Just one, me.

Daniel, my son, is exactly one fifth of my age. In 21 years time, I will be exactly twice his age. My wife is exactly seven times older than my daughter, Jessica. In 8 years time, my wife will be three times older then Jessica. How old are Daniel and Jessica now?

Answer: Daniel is 7 years old and Jessica is 4 years old

Walking home one day, you take a short cut along the train tracks. The tracks cross a narrow bridge over a deep gorge. At the point you are 3/8 of the way across the bridge, you hear the train whistle somewhere behind you. You charge across the bridge, and jump off the track as the train is about to run you down. As it happens, if you had gone the other way, you would have reached safety just before being run over as well. If you can run ten miles per hour, how fast is the train moving?

Answer: The train is moving at 40 miles per hour. Imagine that a friend is walking with you. When the train whistle blows, you head away from the train, he heads toward it. When he reaches safety, you will be 6/8 (or 3/4)of the way across the bridge, and the train will have just reached the bridge. For the train to cross 4/4 of the bridge in the time you cross the remaining 1/4, the train must be moving four times your speed

If you have three oranges and you take away two, how many will you have?

Answer: Two. The two you took.

I am essential to life on earth! I am split into thirds. Two thirds are the same. One of the thirds is 8. The other two are 1 each. What am I?

Answer: Water

What year comes next in this sequence: 1973 1979 1987 1993 1997 1999

Answer: 2003: they are prime years

A clock chimes 5 times in 4 seconds. How many times will it chime in 10 seconds?

Answer: 11 times. It chimes at zero and then once every second for 10 seconds

If you toss a die and it comes up with the number one 9 times in a row, what is the probability that it will come up with one on the next throw?

Answer: One in six. A die has no memory of what it last showed

There are 10 dogs in a yard. 3 go out, 4 run behind a tree, and 2 jump in the hole. How many are left?

Answer: 10, because none of them left the yard.

If you took two apples from three apples, how many apples would you have?

Answer: Two.

Find the four digit number in which the first digit is one fourth of the last digit, the second digit is 6 times the first digit, and the third digit is the second digit plus 3.

Answer: 1694

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly. The Question: How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly?

Answer: It is not possible to guess only three fruits correctly: the fourth fruit is then correct too! So nobody has guessed three fruits correctly and 123-43-39-31 = 10 people have guessed four fruits correctly

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1,000?

Answer: One hundred - work backwards and you will understand

Why would you not want to be one of Snow White’s dwarfs?

Answer: 6 out of 7 of them aren’t Happy.

When asked how old she was, Suzie replied, “In 2 years I will be twice as old as I was 5 years ago.” How old is she?

Answer: Use some math remember in 2 yrs she's twice as old She's 12 ! 14yr / 2yr = 7yr add 5yr and get 12 years old

A car's odometer shows 72927 miles, a palindromic number. What are the minimum miles you would need to travel to form another?

Answer: 110 miles. (73037)

You have the misfortune to own an unreliable clock. This one loses exactly 24 minutes every hour. It is now showing 3:00am and you know that is was correct at midnight, when you set it. The clock stopped 1 hour ago, what is the correct time now?

Answer: 6:00am: since the clock is losing 24 minutes every hour, for every real hour that has passed, the clock will only show 36 minutes. Since the clock shows 3:00am, we know that 180 clock minutes have passed. This therefore equals 300 real minutes and hence 5 hours. The clock stopped 1 hour ago and the time must now be 6.00am.

I am a number that grows but never grows old. People reach milestones with gifts and gold. What am I?

Answer: One year old!

John is having his 3rd birthday party, but he has been alive for 12 years. How is that possible?

Answer: His birthday is on a leap year! (February 29th)

A woman in California owns a pear tree. This tree is beautiful and has been growing for 50 years on her land. Because the tree produces so well, a local grocery store buys fruit from her. The woman knows that there are 20 branches on the tree. Each branch has exactly 10 boughs. Each bough has 8 twigs. If each twig can grow one piece of fruit, then how many plums will the woman deliver to the local grocery store?

Answer: None. The woman owns a pear tree, not a plum tree.

If someone turned 25 three days ago, but will be 27 next year, when is their birthday?

Answer: Jan. 1.

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

Answer: It was 1/2 its Max height in year 9 so.. Nine Years. Because on the 10th year it doubled for the last time and reached the maximum height

If a wheel has 64 spokes, how many spaces are there between the spokes?

Answer: 64. The space that comes after the 64th spoke, would be just before the first spoke

Three guests check into a hotel room. The manager says the bill is $30, so each guest pays $10. Later the manager realizes the bill should only have been $25. To rectify this, he gives the bellhop $5 as five one-dollar bills to return to the guests. The bellhop realizes that he cannot equally divide the five one-dollar bills among the three guests, so he just gives each guest $1 back and keeps $2 as a tip for himself. As each guest got $1 back, each guest only paid $9, bringing the total paid to $27. The bellhop kept $2, which when added to the $27, comes to $29. So if the guests originally handed over $30, what happened to the remaining $1?

Answer: The $27 paid already includes the bellhop's tip, so $27 + 3x$1 in hand makes $30.

Trains travel from one town to another town all day, always on the same track, always going nonstop and at the same speed. The noon train took 80 minutes to complete the trip, but the 4 PM train took 1 hour and 20 minutes. Why?

Answer: 80 minutes is the same as 1 hour and 20 minutes

A lily pad is growing in a small pond. Every day, it doubles in size. On the 20th day, the lily pad covers the entire pond. Which day was the lily pad only half the size of the pond?

Answer: The 19th day

How many months have 28 days?

Answer: All 12 of them.

Two mothers and two daughters went fishing one day. They were there there the whole day and only caught 3 fish. One mother said: "That is enough for all of us, we will have one each." How can this be possible?

Answer: There was the mother, her daughter, and her daughter's daughter. This equals 2 mothers and 2 daughters.

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

Answer: 50 years old

Numbers and calculations can be daunting to many, so it’s quite normal to see people try to stay clear of any math riddles, for fear of making a fool of themselves. What they fail to understand is that riddles are never meant to make anyone look or feel dumb. They are deceivingly difficult to surprise everyone and prompt a good chuckle once the answer is revealed. That is also the case here. The harder the question looks, the more obvious and simple the answer is likely to be. And are you even sure that these problems have numbers in their solutions?

Last Updated: Tuesday, December 10, 2024