Packet no. 16
I am the smallest number written with two digits. Which number am I?
Show the answer
Answer: ten (10)
Digits are the signs from 0 to 9. We build every number from them, the way we build words from letters.
Maths riddles and number puzzles
From the fingers on one hand to prime numbers. Every riddle practises one maths idea, and a right answer earns a sticker for the album plus a short explanation.
Collected0 of 60 stickers
Name: Date:
I have no corners, and I never start or stop. I roll along like a wheel. What shape am I?
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I have three sides and three corners. Standing on one side, I look like the roof of a house. What shape am I?
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This is how many fingers one of your hands has. Which number is it?
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I look like a snowman: one little ball sitting on top of another. Which number am I?
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When there are no apples in the basket, that is how many there are. I am round like an egg. Which number am I?
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A dog has this many legs, and so does a cat. How many legs is that?
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I have four equal sides and four corners, just like a sugar cube. What shape am I?
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This is how many noses every person has. Which number is it?
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This is how many eyes you have on your face. Which number is it?
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A traffic light shines red, amber and green. How many lights is that?
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This is how many days there are in one week. Which number is it?
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This is how many fingers you have on both hands together. Which number is it?
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Which number is the biggest: three, five or one?
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I am round but stretched out, just like an egg. What shape am I?
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I have five points, and people draw me in the night sky and on top of a Christmas tree. What shape am I?
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Answers (turn the page round) 1. a circle · 2. a triangle · 3. five (5) · 4. eight (8) · 5. zero (0) · 6. four (4) · 7. a square · 8. one (1) · 9. two (2) · 10. three (3) · 11. seven (7) · 12. ten (10) · 13. five (5) · 14. an oval · 15. a star
Name: Date:
I am the smallest number written with two digits. Which number am I?
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I am an even number standing exactly halfway between six and ten. Which number am I?
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Three birds sit on a branch. Two fly away, and then one more lands. How many birds are on the branch now?
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A week has seven days. How many days are in two weeks?
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I have four corners and four sides, but two of my sides are longer than the other two. A classroom board has my shape. What shape am I?
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Turn me upside down and I become a six. Which number am I?
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Which number comes straight after ninety-nine?
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I am an odd number between six and ten, but I am not seven. Which number am I?
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There are four apples on the table. You take two. How many apples do you have?
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What is half of ten?
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How many legs do five birds have altogether?
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How many corners do two triangles have altogether?
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Add eight to me and you get fifteen. Which number am I?
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Some cats sit in a room. Each cat can see three other cats. How many cats are in the room?
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I have six equal square faces, like a dice in a board game. What am I?
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Answers (turn the page round) 1. ten (10) · 2. eight (8) · 3. two (2) · 4. fourteen (14) · 5. a rectangle · 6. nine (9) · 7. a hundred (100) · 8. nine (9) · 9. two (2) · 10. five (5) · 11. ten (10) · 12. six (6) · 13. seven (7) · 14. four (4) · 15. a cube
Name: Date:
Multiply me by any number and you get me again. Which number am I?
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The Romans wrote me with a single letter: X. Which number am I?
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A tray of pie is cut into eight equal pieces. The family eats half. How many pieces were eaten?
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I am three fours, and I am also two sixes. Which number am I?
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I have three digits. The hundreds digit is 7, the tens digit is 0 and the ones digit is 5. Which number am I?
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Double a number and add three. You get eleven. What was the number?
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What is a quarter of twenty?
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How do you write four in Roman numerals? I am not written with four lines.
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What is the biggest number written with two digits?
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Multiply me by myself and you get forty-nine. Which number am I?
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Which number comes next: 3, 6, 9, 12 ...?
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There are twenty-four children in a class. They split into groups of six. How many groups are there?
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Round forty-seven to the nearest ten.
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Each side of a square is five squares long on grid paper. How many squares long is the whole edge around it?
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I have three sisters and two brothers. How many children are there in our family?
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Answers (turn the page round) 1. zero (0) · 2. ten (10) · 3. four (4) · 4. twelve (12) · 5. seven hundred and five (705) · 6. four (4) · 7. five (5) · 8. IV · 9. ninety-nine (99) · 10. seven (7) · 11. fifteen (15) · 12. four (4) · 13. fifty (50) · 14. twenty (20) · 15. six (6)
Name: Date:
I am a prime number, and yet I am even. There is no other like me. Which number am I?
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Add up all the digits from zero to nine. What do you get?
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A snail climbs a staircase with ten steps. Each day it climbs three steps, and each night it slides back two. On which day does it reach the top?
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Which number comes next: 1, 1, 2, 3, 5, 8 …?
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A father and son are 36 years old together. The father is 26 years older than the son. How old is the son?
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I am a two-digit number. My digits add up to nine. When my digits swap places, I grow by 27. Which number am I?
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What is twenty-five per cent of eighty?
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What is the smallest number that can be divided exactly by three, by four and by five?
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Which number comes next: 1, 4, 9, 16 ...?
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Each boy in a family has as many brothers as sisters. Each girl has twice as many brothers as sisters. How many children are in the family?
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Three cats catch three mice in three minutes. How many cats are needed to catch a hundred mice in a hundred minutes?
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I am a number bigger than one and smaller than a hundred. I am the square of one number and the cube of another. Which number am I?
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How many digits do you write when you write every number from one to twenty?
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Which number continues the sequence: 2, 3, 5, 7, 11 ...?
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What is half of a third of sixty?
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Answers (turn the page round) 1. two (2) · 2. forty-five (45) · 3. on the eighth day · 4. thirteen (13) · 5. five (5) · 6. thirty-six (36) · 7. twenty (20) · 8. sixty (60) · 9. twenty-five (25) · 10. seven (four boys and three girls) · 11. three (3) · 12. sixty-four (64) · 13. thirty-one (31) · 14. thirteen (13) · 15. ten (10)
How maths riddles help children
A riddle turns a sum into a story. Instead of three plus four, a child counts birds on a branch or a cat's legs, so working it out feels like a game. Younger children learn numbers to ten and basic shapes, while older ones practise multiplying, fractions, Roman numerals, sequences and logic.
How to play
Choose an age above the riddle. Up to six, children answer by tapping a picture; from seven they choose or type; from ten they type. Every riddle has two hints and a short explanation after the answer, so even a wrong guess teaches something.
For teachers
Maths riddles work well to open a lesson or fill the last five minutes. Print a worksheet for the chosen age, or open classroom mode and play in two teams.
Numbers and maths: every riddle with its answer
For reading aloud, in class or at home. The answer is hidden under each riddle.
4 to 6 Pick the picture
I have no corners, and I never start or stop. I roll along like a wheel. What shape am I?
Show the answer
Answer: a circle
Did you know? A circle has no corners, which is why a wheel can turn smoothly without bumping.
I have three sides and three corners. Standing on one side, I look like the roof of a house. What shape am I?
Show the answer
Answer: a triangle
Did you know? A triangle has the fewest sides a flat shape with straight sides can have: just three.
This is how many fingers one of your hands has. Which number is it?
Show the answer
Answer: five (5)
Did you know? Two hands have ten fingers, which is why many people first learn to count to ten.
I look like a snowman: one little ball sitting on top of another. Which number am I?
Show the answer
Answer: eight (8)
Did you know? An octopus has eight arms, and a spider has eight legs.
When there are no apples in the basket, that is how many there are. I am round like an egg. Which number am I?
Show the answer
Answer: zero (0)
Did you know? Write a zero after a one and you get ten: 10. Zero is small, but it matters.
A dog has this many legs, and so does a cat. How many legs is that?
Show the answer
Answer: four (4)
Did you know? Animals that walk on four legs are called quadrupeds. Dogs, cats, horses and cows are all quadrupeds.
I have four equal sides and four corners, just like a sugar cube. What shape am I?
Show the answer
Answer: a square
Did you know? A square has four equal sides and four right angles.
This is how many noses every person has. Which number is it?
Show the answer
Answer: one (1)
Did you know? We write one as a straight line: 1. The Romans wrote it with the letter I.
This is how many eyes you have on your face. Which number is it?
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Answer: two (2)
Did you know? Lots of things on your body come in pairs: eyes, ears, hands and feet. A pair means two.
A traffic light shines red, amber and green. How many lights is that?
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Answer: three (3)
Did you know? Red means stop, amber means get ready, and green means go.
This is how many days there are in one week. Which number is it?
Show the answer
Answer: seven (7)
Did you know? Saturday and Sunday are the weekend, and on the other five days we go to school.
This is how many fingers you have on both hands together. Which number is it?
Show the answer
Answer: ten (10)
Did you know? When you count to ten on your fingers, each finger is one number.
Which number is the biggest: three, five or one?
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Answer: five (5)
Did you know? When numbers stand in a row, the bigger number comes later: 1, 2, 3, 4, 5.
I am round but stretched out, just like an egg. What shape am I?
Show the answer
Answer: an oval
Did you know? An oval has no corners, like a circle, but it is longer than it is wide.
I have five points, and people draw me in the night sky and on top of a Christmas tree. What shape am I?
Show the answer
Answer: a star
Did you know? The star we draw has five points, but a real star in the sky is a huge glowing ball.
7 to 9 Choose or type
I am the smallest number written with two digits. Which number am I?
Show the answer
Answer: ten (10)
Did you know? Digits are the signs from 0 to 9. We build every number from them, the way we build words from letters.
I am an even number standing exactly halfway between six and ten. Which number am I?
Show the answer
Answer: eight (8)
Did you know? Even numbers end in 0, 2, 4, 6 or 8. All the others are odd.
Three birds sit on a branch. Two fly away, and then one more lands. How many birds are on the branch now?
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Answer: two (2)
Did you know? When a problem has several steps, solve them in order, one step at a time.
A week has seven days. How many days are in two weeks?
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Answer: fourteen (14)
Did you know? Seven plus seven is fourteen, the same as two times seven. Two weeks are also called a fortnight.
I have four corners and four sides, but two of my sides are longer than the other two. A classroom board has my shape. What shape am I?
Show the answer
Answer: a rectangle
Did you know? A square is a special kind of rectangle: one whose four sides are all equal.
Turn me upside down and I become a six. Which number am I?
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Answer: nine (9)
Did you know? That is why a little line is sometimes drawn under a 6 or a 9, so nobody mixes them up.
Which number comes straight after ninety-nine?
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Answer: a hundred (100)
Did you know? A hundred is the first number with three digits. Ten tens make one hundred.
I am an odd number between six and ten, but I am not seven. Which number am I?
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Answer: nine (9)
Did you know? Odd numbers end in 1, 3, 5, 7 or 9.
There are four apples on the table. You take two. How many apples do you have?
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Answer: two (2)
Did you know? In a word problem, the most important thing is to read the question right to the end.
What is half of ten?
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Answer: five (5)
Did you know? Half of a number is the number that, added to itself, makes the whole: 5 + 5 = 10.
How many legs do five birds have altogether?
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Answer: ten (10)
Did you know? To count legs, first find out how many one animal has, then count in jumps.
How many corners do two triangles have altogether?
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Answer: six (6)
Did you know? Two times three is six. Multiplying is a quick way of adding the same number.
Add eight to me and you get fifteen. Which number am I?
Show the answer
Answer: seven (7)
Did you know? Taking away is the opposite of adding: 15 − 8 = 7, and 7 + 8 = 15.
Some cats sit in a room. Each cat can see three other cats. How many cats are in the room?
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Answer: four (4)
Did you know? Each cat sees the other three, not itself. So it is the same four cats.
I have six equal square faces, like a dice in a board game. What am I?
Show the answer
Answer: a cube
Did you know? A cube has six faces, eight corners and twelve edges.
10 and 11 Type the answer
Multiply me by any number and you get me again. Which number am I?
Show the answer
Answer: zero (0)
Did you know? Any number multiplied by zero gives zero, and any number multiplied by one stays the same.
The Romans wrote me with a single letter: X. Which number am I?
Show the answer
Answer: ten (10)
Did you know? Roman numerals use letters: I is 1, V is 5, X is 10, L is 50 and C is 100.
A tray of pie is cut into eight equal pieces. The family eats half. How many pieces were eaten?
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Answer: four (4)
Did you know? We write a half as 1/2. Half of eight is four, and a quarter of eight is two.
I am three fours, and I am also two sixes. Which number am I?
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Answer: twelve (12)
Did you know? Twelve splits into equal groups in many ways: into 2, 3, 4 or 6. Twelve of something is called a dozen.
I have three digits. The hundreds digit is 7, the tens digit is 0 and the ones digit is 5. Which number am I?
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Answer: seven hundred and five (705)
Did you know? Zero holds the place. Without it, 705 would turn into 75, a much smaller number.
Double a number and add three. You get eleven. What was the number?
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Answer: four (4)
Did you know? To find a hidden number, work backwards and do the opposite: subtract instead of adding, divide instead of multiplying.
What is a quarter of twenty?
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Answer: five (5)
Did you know? We write a quarter as 1/4. Two quarters make a half.
How do you write four in Roman numerals? I am not written with four lines.
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Answer: IV
Did you know? IV means five minus one, and VI means five plus one. The position of a letter changes the number.
What is the biggest number written with two digits?
Show the answer
Answer: ninety-nine (99)
Did you know? There are exactly ninety two-digit numbers, from 10 to 99.
Multiply me by myself and you get forty-nine. Which number am I?
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Answer: seven (7)
Did you know? A number multiplied by itself is called its square: 7 × 7 = 49.
Which number comes next: 3, 6, 9, 12 ...?
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Answer: fifteen (15)
Did you know? These are the multiples of three: what you get when you multiply three by 1, 2, 3, 4 and 5.
There are twenty-four children in a class. They split into groups of six. How many groups are there?
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Answer: four (4)
Did you know? Dividing tells you how many times one number fits into another: 24 ÷ 6 = 4.
Round forty-seven to the nearest ten.
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Answer: fifty (50)
Did you know? Rounding helps you estimate quickly: 47 is about 50.
Each side of a square is five squares long on grid paper. How many squares long is the whole edge around it?
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Answer: twenty (20)
Did you know? The distance around a shape is called its perimeter. For a square it is four times one side.
I have three sisters and two brothers. How many children are there in our family?
Show the answer
Answer: six (6)
Did you know? The trap in questions like this is forgetting the person asking.
12+ Hard riddles
I am a prime number, and yet I am even. There is no other like me. Which number am I?
Show the answer
Answer: two (2)
Did you know? The primes are 2, 3, 5, 7, 11, 13 and so on. Every other even number can be divided by two, so it cannot be prime.
Add up all the digits from zero to nine. What do you get?
Show the answer
Answer: forty-five (45)
Did you know? Pairing up is an old trick. A well known story says the mathematician Gauss added all the numbers from 1 to 100 this way as a boy.
A snail climbs a staircase with ten steps. Each day it climbs three steps, and each night it slides back two. On which day does it reach the top?
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Answer: on the eighth day
Did you know? The trap in puzzles like this is the final step. Draw the stairs and follow the snail day by day.
Which number comes next: 1, 1, 2, 3, 5, 8 …?
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Answer: thirteen (13)
Did you know? This is the Fibonacci sequence. You can find the same numbers in the spirals of sunflower seeds and pine cone scales.
A father and son are 36 years old together. The father is 26 years older than the son. How old is the son?
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Answer: five (5)
Did you know? Check the answer: 5 + 31 = 36 and 31 − 5 = 26. Checking is half the work.
I am a two-digit number. My digits add up to nine. When my digits swap places, I grow by 27. Which number am I?
Show the answer
Answer: thirty-six (36)
Did you know? A number whose digits add up to nine can always be divided by nine. Try it: 36 ÷ 9 = 4.
What is twenty-five per cent of eighty?
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Answer: twenty (20)
Did you know? Per cent means out of a hundred. Fifty per cent is a half, and twenty-five per cent is a quarter.
What is the smallest number that can be divided exactly by three, by four and by five?
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Answer: sixty (60)
Did you know? The smallest number that all the given numbers divide into is called the lowest common multiple.
Which number comes next: 1, 4, 9, 16 ...?
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Answer: twenty-five (25)
Did you know? These are square numbers. You can arrange that many dots into a square.
Each boy in a family has as many brothers as sisters. Each girl has twice as many brothers as sisters. How many children are in the family?
Show the answer
Answer: seven (four boys and three girls)
Did you know? Each boy has three brothers and three sisters, and each girl has four brothers and two sisters.
Three cats catch three mice in three minutes. How many cats are needed to catch a hundred mice in a hundred minutes?
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Answer: three (3)
Did you know? First work out what one cat does. That is how you solve every workers and time puzzle.
I am a number bigger than one and smaller than a hundred. I am the square of one number and the cube of another. Which number am I?
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Answer: sixty-four (64)
Did you know? 64 is 8 × 8, and also 4 × 4 × 4.
How many digits do you write when you write every number from one to twenty?
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Answer: thirty-one (31)
Did you know? Nine one-digit numbers and eleven two-digit numbers: 9 + 22 = 31 digits.
Which number continues the sequence: 2, 3, 5, 7, 11 ...?
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Answer: thirteen (13)
Did you know? These are the prime numbers. There are infinitely many of them, which was proved back in ancient Greece.
What is half of a third of sixty?
Show the answer
Answer: ten (10)
Did you know? Half of a third is a sixth. Sixty divided by six is ten.
What we practise
- 4 to 6
- counting to ten, zero, circles and triangles
- 7 to 9
- digits, even numbers, two-step adding and taking away, rectangles
- 10 and 11
- multiplying, halves, Roman numerals, hundreds and tens, working backwards
- 12+
- prime numbers, the Fibonacci sequence, age puzzles, digit sums