Adding and Subtracting

Procedure 2.4. How much is 3 + 5?

  1. Type 3 and then press +. Notice that in the result field, 3 is a simple value displayed on just one line, with no monetary unit.

  2. Type 5 and then press the Enter button or the Enter key. The result 8 appears on the right.

Procedure 2.5. You received 100 US dollars and paid 32.50 euros for a book, how much do you have left in your bank account?

  1. Make sure that the variable exchange rates are available. If not, press the Settings... to select either Euro, European Central Bank or Euro, Time Genie. Now select the USD - US dollar item in the scroll down list on the bottom. If you have no Internet access, that item won't be available as the latest variable rates between the euro and the dollar cannot be determined.

  2. Type 100 and then press $.

  3. Press the - button or the - key. Notice the - sign in the leftmost part of the Input display.

  4. Type 32,50 or 32.50 and then press .

  5. Read the result in the Result display on the right. The exact value might depend on latest exchange rates. Notice that during the whole computation you've been able to read the values both in euro and in US dollars. Pay attention to the fact that different data sources (ECB or TG) might not provide the same conversion rate between the euro and the dollar.

Procedure 2.6. You pay a 32.50 € book with a 500 FF banknote. How much was the clerk supposed to give you back, in euro notes and coins?

  1. Select the FRF - French francs item in the currencies drop down list if not already selected.

  2. Type 32.50 or 32,50 and then press . You can also type 32.5 without the trailing 0.

  3. Press the - button or the - key.

  4. Type 500 and press the FF button or the F key.

  5. The result -43.72 € is negative, indicating that change money has to be given back to the customer. The +/- button or the S key permit you to change the sign of the result.


Do not try to add euros to simple values (with no currency unit): it won't work, for the same reason you cannot add 5 meters to 3 kilograms.