A simple training tool for basic calculations

A simple training tool for basic calculations. The numbers were generated at
http://3ddoctors.net/templates/textsigns/textsign.html
The thickness of the numbers in the stl-files is 1mm. If you prefer thicker numbers, just adapt the height on the 3ddoctors site.
The calculator will be more attractive when the print is paused after the last layer and the equal sign starts printing. At that moment, change the color of the filament. Alternatively, paint the signs in a darker color acrylic paint,