Ruler shown in picture is not necessary! I just think it happened to be laying on the table when they began assembly. :)
For older children, you could also try putting the globe together without using the numbers on the back. That will be a great review after we learn each country next year too!
This puzzleball globe is currently selling for $24.99 at Timberdoodle and is also included in their 2016 3rd grade curriculum kit.
**I received a free copy of this product through Timberdoodle in exchange for my honest review. I was not required to write a positive review nor was I compensated in any other way. All opinions I have expressed are my own or those of my family. I am disclosing this in accordance with the FTC Regulations.