🔢 Math riddles for kids with answers

Grab a pencil if you need one. Every answer below is explained, so you can check how it works.

1. What number comes next: 1, 1, 2, 3, 5, 8, ...?

   💡 Hint

   Add two neighbors together.

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   13. Each number is the sum of the two before it (5 + 8 = 13).

2. I am an odd number. Take away one letter and I become even. What number am I?

   💡 Hint

   Think about how the number is spelled.

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   Seven. Take away the "s" and you get "even."

3. A bat and a ball cost $1.10 together. The bat costs $1.00 more than the ball. How much does the ball cost?

   💡 Hint

   It's not 10 cents - check that answer.

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   5 cents. The bat costs $1.05, and $1.05 + $0.05 = $1.10.

4. What is half of two plus two?

   💡 Hint

   Do the "half" part first.

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   3. Half of two is 1, and 1 + 2 = 3.

5. How many times can you subtract 5 from 25?

   💡 Hint

   What does 25 turn into after the first time?

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   Once. After that, you're subtracting from 20, not 25.

6. A doctor gives you 3 pills and tells you to take one every half hour. How long until they're all gone?

   💡 Hint

   The first pill is taken right away.

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   One hour. Take one now, one after 30 minutes, and the last one after 60 minutes.

7. When I was 6, my sister was half my age. Now I'm 70. How old is my sister?

   💡 Hint

   The difference between ages never changes.

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   67. She was 3 when I was 6, so she is always 3 years younger.

8. How can you add eight 8s together to get 1,000? (Only addition!)

   💡 Hint

   Some 8s can sit next to each other to make bigger numbers.

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   888 + 88 + 8 + 8 + 8 = 1,000

9. A snail is at the bottom of a 10-foot well. Each day it climbs up 3 feet, and each night it slides back 2 feet. How many days does it take to get out?

   💡 Hint

   On the last day, the snail doesn't slide back.

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   8 days. After 7 days and nights it is at 7 feet. On day 8 it climbs 3 feet, reaches 10 feet and is out before it can slide back.

10. Which three positive whole numbers give the same answer when you add them and when you multiply them?

    💡 Hint

    Try the smallest numbers first.

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    1, 2 and 3. 1 + 2 + 3 = 6 and 1 × 2 × 3 = 6.

11. If 5 cats catch 5 mice in 5 minutes, how many cats are needed to catch 100 mice in 100 minutes?

    💡 Hint

    How many mice does one cat catch in 5 minutes?

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    5 cats. Each cat catches 1 mouse every 5 minutes, so in 100 minutes each cat catches 20 mice, and 5 cats catch 100.

12. A patch of lily pads doubles in size every day. On day 48 it covers the whole pond. On what day did it cover half of the pond?

    💡 Hint

    Go back just one day.

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    Day 47. It doubles from half to whole in one day.