Maths Riddles for Kids with Answers

25 riddles

A maths riddle is not a sum with a story round it. The arithmetic in a good one is easy enough that a seven-year-old can do it in their head — the difficulty is realising which sum to do, and that is a completely different skill from the one school is drilling.

These 25 are ours. Several of them are traps: the obvious answer is wrong, and finding out why is the entire lesson.

A farmer has 17 sheep. All but 9 run away. How many are left?
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Nine. «All but nine» means nine stayed
There were three candles burning. The wind blew two of them out. How many candles are left?
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Three. Blowing one out does not remove it
If you have one match and you walk into a dark room with a lamp, a stove and a candle, what do you light first?
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The match
A clock strikes six in five seconds. How long does it take to strike twelve?
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Eleven seconds. You count the gaps, not the strikes
I am the only even number that cannot be divided by anything but one and myself. What am I?
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Two
I am a two-digit number. My digits add up to nine and my second digit is twice the first. What am I?
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36
How many months of the year have 28 days?
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All twelve
A snail climbs three metres up a wall each day and slips back two each night. The wall is five metres. On which day does it reach the top?
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The third day. It climbs out before it can slip
If two cats catch two mice in two minutes, how many cats do you need to catch a hundred mice in a hundred minutes?
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Two
What weighs more: a kilo of gold or a kilo of grass?
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Neither. They both weigh a kilo
Add me to myself and multiply by four. Divide by eight and you have me again. What am I?
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Any number at all
A book has 100 pages. How many times does the digit 9 appear?
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Twenty times
Two fathers and two sons went fishing and caught three fish, one each. How?
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There were three of them: a grandfather, a father and a son
How can you take two from five and leave four?
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Remove F and E from FIVE: IV is left, which is four
What is the next number: 1, 4, 9, 16, 25…?
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36. They are the numbers multiplied by themselves
Which is heavier: a hundred grams of feathers or ninety grams of lead?
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The feathers, by ten grams
I am thinking of a number. If I take away four I get double three. What is it?
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Ten
A rope ladder hangs over the side of a ship, with rungs thirty centimetres apart. The tide rises a metre. How many rungs go under?
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None. The ship rises with the tide
If it takes six minutes to boil one egg, how long for three eggs in the same pan?
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Six minutes
How many times can you subtract five from twenty-five?
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Once. After that it is twenty, not twenty-five
What has a value of ten but takes up no space at all when written after a one?
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A zero
I have 5 fingers on one hand, 5 on the other, and 50 on my feet. What am I?
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Nothing. Somebody miscounted
Divide thirty by half and add ten. What do you get?
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Seventy. Dividing by a half means multiplying by two
A pencil and a rubber cost £1.10 together. The pencil costs a pound more than the rubber. What does the rubber cost?
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Five pence
What is the smallest number you can make with a one and a two?
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One half — if you write it as a fraction

How to ask them

With maths riddles the temptation is to let a child get out a pencil, and it is usually worth resisting for the first minute. These are built so the numbers stay small; if a child is writing, they have probably misread the question rather than found a hard sum. The other habit worth building is asking for the reasoning even when the answer is right. «How did you get that?» separates the child who understood the trick from the child who guessed — and with these riddles guessing gets you the right answer surprisingly often. And when they fall for one of the traps, go back to the exact word that fooled them and read the question again slowly. Almost every trap here lives in one word.

More riddles

After the riddles, a story: illustrated bedtime stories on Marytale →

All 25 riddles on this page are written by Marytale for children aged 7 to 10. None is copied from another collection. Written by Marytale.