Four Functions, %
Std Memory Functions
Printing Calculator

"The HP-10 was a complete departure from previous HP calculators - neither a financial model nor a technical one, but instead an "adding machine". It was the smallest HP calculator so far to have a built-in printer - easily held in one hand, it did not use RPN, it had only + - x - and % keys; not even a square root, though it had an automatic constant feature and a single memory register. No
wonder the calculator's codename was KISS - "Keep It Simple, Stupid". " Wlodek Mier-Jedrzejowicz.
Source: MoHPC - The Museum of HP Calculators

X-Number World