The 35 Very Best Math Riddles

Here are 35 maths riddles of all different levels of difficulty! We begin with fun riddles, then move to medium and challenging. Is your aim to give your brain a workout? Then you are in the right place! Enjoy but don’t think too hard and hurt yourself…

Fun Math Riddles

1. What did one math book say to the other?

        “I have so many problems”

2. Once I’m 24. Twice I’m 20. Three times I’m inappropriate. What am I?

        The letter “X”

3. An apple is 40 cents, a banana is 60 cents. and a grapefruit is 80 cents. How much is a pear?

        The price of each fruit is calculated by multiplying the number of vowels by 20 cents, so the answer is forty cents.

4. How many bricks does it take to complete a building made entirely of bricks?

        One. The last one!

5. A family has five sons, each of them has a sister. How many kids are there in total?

        Six children. Five sons and one shared sister.

Why was 6 afraid of 7?

Because 7 ate 9 (789)

7. Give me an x, and the answer will face you. Give me a cross, It will turn its back on you. What am I?

        The number nine! 9×9 is 81 and 9+9 is 18.

8. How many eggs can you put in an empty basket?

        One, after this the basket is no longer empty

9. Where can you buy a ruler that is 3 feet long?

        A yard sale

10. When things go wrong, what can you always count on?

        Your fingers.

Medium Riddles

1. 5 friends had to guess the exact numbers of balls in a box. Friends guessed as 31 , 35, 39 , 49 , 37, but none of them were right.The guesses were off by 1, 9, 5, 3, and 9 (not in order). How many balls are in the box?

         40

Using four eights (8) and a one (1) and one mathematical symbol , create the number 100

188-88

3. A train leaves from point A for point B at 80km/h. After 30 minutes, another train leaves from point B for point A at 60km/h. Which of the trains will be further away from point A when they meet ?

        When the trains meet, they will be equally distant from point A.

4. I have a half-cup of tea and a half-cup of coffee. I take one teaspoon of tea and mix it with my coffee, then I take one teaspoon of this mixture and mix it with the tea. Which cup contains more of its original contents?

        Both are equal

5. Can you put either addition (+), subtraction (-), multiplication (x), division (/) and parenthesis among five number 7s to make a target result number 50? 77777=50

        ((7 x 7 x 7) + 7) / 7= 50 or ((7 / 7) / 7 +7) x 7 = 50

6. At 8 AM, a clock ticks 8 times. The time between first and last ticks is 35 seconds. How long does it tick at 11 Noon?

        50 seconds

7. Hunter decided to give bracelets to his friends on his Birthday. If he gives 3 bracelets to each friend, one friend will get only 1 bracelet. Also, if he gives 2 bracelets to each friend, he will be left with 13 bracelets. How many bracelets did Hunter give out on his Birthday? And how many friends are there?

         43 bracelets and 15 friends

8. Find the next 2 numbers in the series: 1, 8, 11, 69, 88, 96, 101, 111, 181, …

         609, 619 (invertible numbers)

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

10. If you multiply this number by any other number, the answer will always be the same. What number is this?

        Zero

Challenging Riddles

1. My twin lives at the reverse of my house number. The difference between our house numbers ends in two. What are the lowest possible numbers of our house numbers?

        19 and 91

2. When shipping something, Hank can place ten small boxes or eight large boxes into a carton. A total of 96 boxes were sent in one shipment and the number of small boxes was less than large boxes. How many cartons did he ship?

        11

3. A snail is at the bottom of a 20-metre pit. Every day the snail climbs 5 meters up but at night it slides down 4 meters. How many days will it take before the snail reaches the top?

        16 days

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?

Two dozen

5. You know 2 + 2 comes to the same as 2 x 2. Now find a set of three different whole numbers whose sum is equal to their total when multiplied.

        1,2, and 3

6. Sarah noticed that the amount she was paying for her lunch was a rearrangement of the digits of the amount of money she had in her pocket, and that the money she had left over was yet another rearrangement of the same three digits! How much money did Sarah start with?

        $9.54

7. One out of 9 otherwise identical balls, one weighs 500 grams more. 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.

8. 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, 3 flowers

9. A man dies of old age on his 25th birthday. How is this possible?

        He was born on a leap year

10. There is a certain club which is for men only. 600 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?

        600

11. Stranded on a deserted island, Basil is left with only a 40 litres container of milk. To conserve his milk he decides that on the first day he will drink one litre of milk and then refill the container back up with water. On the 2nd day he will drink 2 litres and refill the container. On the 3rd day he will drink 3 litres and so on… By the time all the milk is gone, how much water has he drunk?

        780 litres of water

One side of the bottom layer of a triangular pyramid has 11 balls. How many balls are there in the whole pyramid? Note that the pyramid is equilateral and solid.

286 balls

13. A bag of jelly beans was divided between Mayank and Steve. Mayank said, “Not fair! You have 3 times as many jelly beans as me.” Steve said, “OK, I will give you one jelly bean for each year of your age.” Mayank replied, “Now, you have twice as many jelly beans as I have.” “This is fair as I am twice your age”, said Steve. While Steve wasn’t looking, Mayank took apricots from Steve’s pile equal to Steve’s age. Who has more apricots now?

        They both have the same number of apricots

14. Jerome is six years old and his sister is half his age. How old will his sister be when he is 40?

        37

Question 15# You are in a darkened room. Someone hands you a normal deck of 52 cards. He tells you that 13 of the 52 cards are face-up, the rest are face-down. These face-up cards are distributed randomly. Your task is to split up the deck into two piles, using all the cards, such that each pile has the same number of face-up cards. The room is dark and you can’t see the deck.  How can you accomplish this?

Answer – Take the first 13 cards off the top of the deck and flip them over. This is the first pile. The second pile is just the remaining 39 cards as they started. This works because if there are X face-up cards within the first 13 cards, then there will be (13 – X) face up cards in the remaining 39 cards. When you flip those first 13 cards, X of which are face-up, there will now be X cards face-down, and therefore (13 – X) cards face-up, which, as stated, is the same number of face-up cards in the second pile.