## Why did the math riddle cross the road?

Like Mac and Cheese or an ice cream cone on a hot summer’s day, silly riddles are an essential comfort of a joyful childhood. No matter how corny a riddle is, it is pure magic to hear a child shriek with laughter at the goofy wordplay and puns of a classic riddle.

Q. Why did the Roman chicken cross the road?

A. She was afraid someone would Caesar!

Q. Why did the chicken cross the playground?

A. To get to the other slide.

Q. Why did the horse cross the road?

A. Because the chicken needed a day off.

Q. Why did the cow cross the road?

A. To get to the udder side!

Those are fun, but for math-loving parents and kids, riddles can be enriching beyond simple puns and wordplay. There is a whole sub-genre of riddles– math riddles– that take the old classics’ best qualities while mixing in numerical literacy and mathematical reasoning. Cool!

## What is a riddle? Did you know that linguists divide riddles into two types?

Many of us have had the wonderful experience of hearing a riddle so ingenious it sticks with you for days while you try to puzzle out the answer. There’s no satisfaction like finally solving it! But fewer people know how riddles intersect with mathematical thinking and how they can help your child’s mind grow. We’ll explore those ideas in this ultimate guide to math riddles, but first, let’s look at the two types of riddles.

The definition of what counts as a riddle is quite broad. In general, riddles are short, clever questions that challenge you to stretch your mind to find a solution. There are two main genres of riddles: enigmas and conundrums. Enigmas are more serious and often symbolic, while conundrums are more clever and tricky, often including a pun in the question or answer. One finds silly puns like this in conundrums: “What is the difference between jewelers and jailers?” – “One sells watches while the other watches cells.”

### The etymology of “riddle” suggests riddles emerged independently in many different cultures.

The word ‘riddle’ and the word ‘read’ are both derived from the same ancient word. Can you guess what it is? It is the Old English word ræ̅dan, meaning ‘to guess.’ There are similar words in other ancient languages, such as riedsal in Old Frisian, radisli in Old Saxon, and Rätsel in German. All of these words have similar meanings, having to do with questions and deduction. Although the word’s sound has changed over time, the connotations have always been similar.

## Let’s give some math riddles a try!

A grandfather, two fathers, and two sons went to the movie theater together. Everyone bought one movie ticket each. How many tickets did they buy in total?

The answer is three! The grandfather is also a father, and the father is also a son.

Here is another one for you to try!

5+5+5=550. Draw one straight line to make the equation true.

There are two ways to solve this one. Most people who solve it get the first solution: draw a line across the equal symbol to make it “not equal to.” The other way is to draw a straight line on the first plus sign, making it a number 4. Now the equation looks like 545+5=550, which is true!

Most people give up before they get either answer. If your kids are stuck on a riddle, try to give them clues instead of the solution. This helps build their perseverance when they get tricky math problems in school.

If you liked the last riddle, this next one relies on the same sort of symbolic manipulation. Knowing the answer to the one above might make this one easier.

5-5=550. Draw one mark to make the equation true.

Did you think of drawing a dot (indicating multiplication) between the “55” and the “0” on the equation’s right side? That would make both sides equal to zero.

According to recent research, a great way to bond with your children is to face and overcome challenges together. Through the shared struggle and triumph, your children connect with you more deeply. More importantly, you’ll share the positive experience of working together and succeeding. Projects like building robotics kits, making things with Arduino or Raspberry Pi, or even building a PC together, can be great to do with older kids. With early elementary school kids, doing math riddles is a great small-scale team experience. Like Lego projects or playing with Scratch, doing math riddles together builds team problem-solving skills that can evolve into larger, more complicated projects. Simply, riddles aren’t just fun; they are a great way to build problem-solving camaraderie with your child.

Math riddles are also beneficial for your child’s development. Research on “grit” or mental toughness shows that the ability to stick with demanding tasks can be a better predictor of positive outcomes than intelligence. When children fail, they have the chance to try again. Learning how to persevere after a failure, or in the case of a riddle, not getting the correct answer, is the essence of building grit. One nice feature of math riddles is that not getting the answer doesn’t have any consequences; through math riddles, kids can learn that failing is safe, which helps them take positive risks later. It is precisely those kinds of positive risks that allow entrepreneurs to grow companies and inventors to try again and again when their first attempts go sideways.

## Here are some riddles for you to try!

When Emma was eight years old, her dad was 31. Now, he is twice Emma’s age. How old is Emma?

Is this one easy or hard? Here’s the answer: the difference between the ages 31 and 8 is 23 years. So Emma must be 23 years old now. At any other age (besides 23), her dad wouldn’t be precisely double.

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?

Many answers work for this one. They could be 51 and 15 years old, 42 and 24 years old, or 60 and 06 years old. Do you see the pattern?

I add five to nine and get two. The answer is correct, but how?

This one is tricky. In fact, it is so tricky that it falls into the category of “trick questions.” The numbers are referring to time and hours in a day. When it is 9 AM, add 5 hours, and you will get 2 PM. Sometimes trick questions don’t seem fair, but they help us think about problems more broadly, which is a great skill for kids to learn.

Here is another “trick” question!

How do you make the number 7 even without addition, subtraction, multiplication, or division?

Drop the “S.” Then it changes from “seven” to “even.”

## Math riddles help develop problem-solving skills.

Kids can develop problem-solving skills in so many ways. There are logic puzzlesmath competitions, and extracurricular math classes (like the IMACS math program) that grow these skills. Along with these proven pathways, parents can add math riddles to the mix. If you want to raise a problem-solver who excels in higher math later in life, it’s a great addition to an early elementary extracurricular plan. Math riddles introduce kids to the creativity and fun of mathematics.

Riddles also allow students to practice math without a teacher or parent supervising or helping. Later in this ultimate guide to math riddles for kids, we have some great book suggestions that many kids will find irresistible. Because these short, fun problems rarely require higher-level skills that kids might not know, a math riddle book can be a great gateway to more independent learning.

There are considerable benefits to students solving problems on their own. Several studies show that independent work helps students improve their problem-solving skills and their tenacity in sticking with complex problems. Riddles also can have benefits for kids who struggle with paying attention. If your child resists doing math, including an element of fun in math can change your child’s belief that math is boring. Every riddle presents a new game, and many riddles are humorous or relatable to kids. Additionally, less tricky riddles allow kids to succeed in math, boosting their confidence across all areas.

How many times can you subtract the number 5 from 25?

Hey! This one doesn’t seem fair! Here is the tricky answer: Only once! After you subtract 5, it’s 20, not 25. With a problem like this one, you can encourage your child to give the riddle to other grown-ups. Kids can learn to be more comfortable with getting answers wrong when they see that adults get things wrong too!

Multiply all the numbers on a telephone’s dial pad. What do you get?

You can use the phone app on your phone to show your child all the numbers if they are struggling. The answer is zero. Many people start multiplying from the one on the number pad and multiply up to quite large numbers before realizing the “trick.”

There is an empty basket that is one foot in diameter. Can you tell me the total number of eggs that you can put in an empty basket like this?

Another trick question! You can only put one egg in. Why? Because once you place that first egg, the basket doesn’t remain empty anymore. This one is a lot like the “subtract 5 from 25” problem above. Even though these types of problems do not help with math skills directly, listening closely and understanding the question’s details is a crucial part of succeeding, not only in math but also in life!

Eggs are \$0.12 a dozen. How many eggs can you get for a dollar?

This little math riddle is neat. While it is straightforward, it requires thinking through several steps to realize that the answer is 100 eggs, at one penny each!

If there are four apples and you take three, how many do you have?

More tricks! You took three apples, so you now have three apples. Are they getting easier now that you have done a few that are this style?

## Math riddles help with language skills. Higher scores on the SAT through riddles? Yes!

All of those trick problems above show that math riddles can be rooted in language comprehension as much as logic. When kids are working on math riddles, they are also building critical reading skills.

Even if your child is a strong reader, practicing critical reading skills is always advantageous. There is a massive difference between reading and reading comprehension. In the United States, the literacy rate is 86 percent, but fewer than 7000 people per year get a perfect SAT reading comprehension sub-test score. It may seem absurd to connect first-grade math problems with SAT scores ten years later but looking for “tricks” and reading with a critical eye is a skill acquired indirectly from a lifetime of commitment to active reading.

What did zero say to eight?

Some of the best math riddles are just fun! What did zero say to eight? Nice belt!

I have a pound of feathers and a pound of iron? Which one weighs more?

Both of them are the same weight. A pound is a pound no matter the object. There would be a lot more feathers!

A duck costs \$9, a spider costs \$36, and a bee costs \$27. How much will a cat cost?

This riddle is fun because it relies on the problem-solver to figure out the question. What does each creature cost per leg? The answer is \$18, \$4.50 per leg!

A man is twice as old as his little sister. He is also half as old as their dad. In fifty years, his little sister will be half as old as their dad. How old is the man right now?

Answer: He is 50 years old.

## Math riddles can boost mental health.

Riddles will boost your child’s mood, make them laugh, and give them a sense of accomplishment. Riddles and puzzles can also reduce stress. The reason puzzles and riddles can be beneficial for kids’ mental health is related to how they engage the brain. Math riddles cause your child to narrow his or her focus to one specific task. By forcing the brain to focus on a single task exclusively, math riddles can relieve stress triggered by scattered focus and multi-tasking.

### Let’s get some of that stress relief…

What is the following number in the pattern 1, 11, 21, 1211, 111221, 312211?

The answer to this one is 13112221. If you didn’t get the answer, try to see if you can figure out the pattern before you keep reading!

Here’s the explanation: when you say the number aloud, it describes the number before it, so 1 = One, one written as 11, then you have two ones = 21, and so on.

Robin tosses a coin ten times and got heads every time. If he throws it again, what are the odds he will get heads again?

Even if Robin got heads 20 times in a row (assuming it is a fair coin), the odds for that next throw will still 50 percent. The 11th coin toss (or 21st, or any other) is not affected by earlier tosses.

If it took six people 9 hours to build a barn, how long would it take 12 people to build the same barn?

## Math riddles and math jokes for you to try (with answers!)

We’ve just shared so many different kinds of math riddles, but there is one more nuance to explore. There is a very fine line between a brain teaser, a funny math riddle, and a math joke. So, while some of those riddles above might be hard enough to stump your math teacher, these math riddles are designed just to make you laugh.

Did you hear about the mathematician who’s afraid of negative numbers?

Answer: He will stop at nothing to avoid them.

Did you hear the one about the statistician?

Where do fish keep their money?

## Here are some more great math riddles.

There is no wrong time to try a math riddle. They’re great for car rides, homeschooling pods, waiting rooms, and classrooms. Encourage your kids to share their favorite ones with other adults. That’s a great way to get them asking for new riddles that they can then pass forward again.

How can you take two from 5 and leave 4?

Answer: Think of the spelling: F I V E. Remove the letters F and E from five, and you have IV, the Roman numeral for 4. A problem like this is a great way to wrap up teaching young kids about Roman numerals.

1=3, 2=3, 3=5, 4=4, 5=4, 6=3, 7=5, 8=5, 9=4, 10=3, 11=? 12=? Can you complete the sequence?

Did you figure out that the answer is 6? The pattern is that the numbers equal the number of letters in their spelling (1 = one, and “one” has three letters, or: 3).

Does your child like problems that require doing some math? Here are a few.

There are seven children on the bus. Each child has seven backpacks. In every backpack, there are seven large cats. For each large cat, there are seven small cats. How many legs are on the bus, not including the driver?

That’s a lot of legs! There are 10,990 without counting the driver. Here’s a breakdown. Seven children each with seven backpacks = 49 backpacks. Seven big cats in each backpack = 49 x 7 = 343 large cats. 4 legs for each large cat = 1,372 legs. Seven small cats for each large cat = 7 x 343 = 2401 small cats. 4 legs for each small cat = 7 x 2401 = 9,604 legs. 2 legs for each child = 14 legs. 1,372 legs + 9,604 legs + 14 legs = 10,990 legs.

Can you write down eight eights so that they add up to one thousand?

Answer: 888 + 88 + 8 + 8 + 8 = 1000

This one most people don’t get. Can you get it?

You want to boil an egg for two minutes, but you only have a three-minute hourglass, a four-minute hourglass, and a five-minute hourglass. How can you cook the egg for only two minutes?

Answer: Once the water is boiling, turn the three-minute hourglass and five-minute hourglass over. When the three-minute hourglass runs out, put the egg in the boiling water. When the five-minute hourglass runs out, two minutes have elapsed, and it is time to take the egg out of the water. The four-minute hourglass is just in the question to trip you up.

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. In this case, you would only be buying three tickets, whereas if you take the same friend twice, you are purchasing four tickets.

## We have some kids’ math riddles book recommendations for you!

If you have puzzled through all of these riddles and are hungry for more, here are some of our favorite books of math riddles for kids.

Math Riddles For Smart Kids

101 Math Puzzles, Riddles, and Brain Teasers for Kids

Difficult Riddles For Smart Kids: 300 Difficult Riddles And Brain Teasers Families Will Love

The Everything Kids’ Math Puzzles Book: Brain Teasers, Games, and Activities for Hours of Fun

## Does your child like these math riddles? What can you do next?

If your child enjoys these math riddles, they’ll love IMACS. The IMACS math program is much more challenging and serious than these silly math riddles, but like the puzzles above, IMACS is fun! Kids in the IMACS program grow to love math and often excel at the highest levels. Read some of our graduate stories and find out how IMACS brings all of the joy of these math riddles to the vital work of mastering mathematical reasoning. If you are ready to see it yourself, IMACS has a free placement class your child can try.