Clearing Data Storage Registers; Storage Register Arithmetic - HP -10C Owner's Handbook Manual

30 Section 2: Memory Stack, LAST X, and Data Storage

Clearing Data Storage Registers

Pressing ´CLEARQ (clear registers) clears the contents of all data
storage registers, the stack, and the LAST X register to zero. To clear a single
data storage register, store zero in that register.

Storage Register Arithmetic

O (+, -, *, ÷) n (storage register arithmetic). This sequence uses
the number in the display (X-register) to perform arithmetic upon the contents
of a specified storage register n. The key sequence is O followed by an
arithmetic function key, followed in turn by the register address (0 through 9).
The result of any storage register arithmetic operation is placed in the specified
data storage register.
represent the current status of the memories, then executing O÷1 results
in: