Blog

Difficulty: Fun 

Here are eight 8s 

8 8 8 8 8 8 8 8 

Put some plus signs in there to make 1000.

Need a hint?

Grab a piece of paper and just try it out! 

If you don’t have a plus sign between the 8s, then they sandwich together to make a bigger number. For example, an 8 next to another 8 makes 88.

Remember that 88 is much bigger than 8 + 8. And 8888 is too big for this puzzle! 

Brainteaser answer

If you play with this puzzle a bit, you’ll realise that you can’t get close to the answer with just 8 and 88. So you’ll need to include 888. 

Then add 88 to get even closer to the target: 

888 + 88 = 976 

You have three 8s left, and you’re 24 short. Fortunately adding three 8s together makes 24! So here’s your solution:

888 + 88 + 8 + 8 + 8 = 1000 

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Your email address will not be published.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 submitting this form, you give CSIRO permission to publish your comments on our websites. Please make sure the comments are your own. For more information please see our terms and conditions.

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