4 ms·

Why does the calculator in the photo have two "=" keys, one black and the other white?

• fjsolwmv 9y ago
  Because black and white are equal, and are means equal, and equal is symmetric, so equal is black and white!
• DanBC 9y ago
  Does this answer? http://www.johnwolff.id.au/calculators/Olivetti/D18/D18.htm http://www.johnwolff.id.au/calculators/Olivetti/D18/D18.htm > Addition and subtraction operate in adding-machine fashion, with numbers being printed as they are entered into the register. C is a correction key which clears the whole of the current entry. The Total (T) key prints the result and clears the register; Sub-total (S) prints the contents and leaves the register unchanged. To encourage the habit of always pressing Total before starting a calculation, the D18 is made to power up with the error lamp lit, so that Total must be pressed before the machine can be used. > Multiplication and division can be entered algebraically using the colour-coded legends printed on the keytops. For example, to multiply 2 by 3, use the white legends and press 2 X 3 =. For operators familiar with the "reverse Polish" entry of the earlier machines, using the moulded legends to the right of the keys will produce the same key sequence and the same result: 2 Enter 3 X . (There is only a single key switch under the Mult/Div/Enter button). the manual doesn't seem to mention it: http://www.curtamania.com/curta/database/brand/olivetti/Olivetti%20Divisumma%2018/more/Olivetti%20Divisumma%2018.pdf http://www.curtamania.com/curta/database/brand/olivetti/Oliv...