Yes it is -- I have a hard time not playing with it. The printed Curta does subtraction but sometimes misses a carry so repeated subtraction like for division is out so I didn't have practice with that.

Pretty good at division now and I am working out square roots.

Alright, I have decided to build some of these to sell. See my post over in the for sale section (https://curta.org/phpBB2/viewtopic.php?p=1622#1622) for details.