Uploaded August 2019 | Updated September 2026, 2 hours ago

---

The Addimat adding machine, also called the Addipresto, was patented by Sergio Lanza in 1956 and made in Italy from then until the late 1960s or early 1970s. The Schnellrechner, also called the Swift Handy calculator, is a clone made in Hong Kong.

For more information about this and other mechanical calculators in my collection, see my website:
jaapsch.net/mechcalc

0:00 Introduction, history
0:33 Addition
1:07 Carry mechanism
1:40 Clearing
1:54 Schnellrechner clone
2:50 Mechanism
4:54 Outro