Blog

Difficulty: Fun

I’m thinking of three numbers.

They are consecutive counting numbers.

When you add the first two numbers together, you get the third number.

What numbers am I thinking of?

Scroll down or click for a hint, or the answer!

brain icon
 

Brainteaser hint

What’s the difference between two consecutive counting numbers?

brain icon

Brainteaser answer

The numbers are 1, 2, 3 as 1 + 2 = 3.

For more brainteasers and puzzles for kids, subscribe to Double Helix magazine!

Subscribe now! button

4 responses

  1. Peter Avatar
    Peter

    There is a second possible answer.
    The numbers are -1, -2, -3 as -1 + -2 = -3.

    1. David Avatar
      David

      Nice one!

      I guess this one only works if you think negative numbers are counting numbers. (And I guess whether you think it’s okay to be counting down) but it’s still a great answer!

    2. David Avatar
      David

      No problems! I love it when people push our puzzles right to the limit. Puzzles can be a bit tricky to write and we sometimes make mistakes, so it’s always nice to get a comment that is adding to the question and not telling us we’ve got it wrong!

  2. Peter Avatar
    Peter

    Thanks. After posting I realised your intent of counting numbers was likely to limit it to positive numbers.

    The fun of many of these brainteasers is in exploring possibilities.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

By posting a comment you are agreeing to the Double Helix commenting guidelines.

Why choose the Double Helix magazine for your students?

Perfect for ages 8 – 14

Developed by experienced editors

Engaging and motivating

*84% of readers are more interested in science

Engaging students voice