Rockwell 320

[Ian Brown]

Hi everyone. I have just inherited a Rockwell 320 from my dad. It was his office calculator. 

I am having trouble finding any instruction manuals on line. 

Please could anyone tell me how the + and - work. It does x and divide and the answer is shown when you press equals. But with the + and - when pressing equals the second number of the sum is displayed and I can’t fathom out the sequence to do + and - calculation. Thank you for any help. Ian. 

[Patrick Souty]

Hi Ian,
These kind of calculators are used primarily for account management and then sum and difference of money amounts.
As to permit fast operation, + and + key are actually combined with the = operation.

That means that you type a number and then press + (or -) and you get, with only one key depressed, the result of the sum (or difference) of the previous amount and the last input number.

I think that the = key of your machine is used only for x and / operations.
But may be some one will be able to provide mode dedicated information about your calculator and correct my answer if needed.