The folding rule is a toolbox must-have. Its clever design links short, rigid segments with small metal hinges making it more ...

Bulky and cumbersome, they’re never by our sides when we need them, and rigid rulers can’t handle curved surfaces. Enter the Rollbe, a coin-sized measuring tool that clips to your key chain.

If you need to use a ruler for any of our lessons and activities, please feel free to print and use this resource. Cut it out, tape it to something more rigid (like a stick) and start measuring ...