# Operating the Curta

### Setting a number on the input section

- Drag the settings lever up or down
- To reset all the setters to zero use the keyboard command:
  - CS for Clear Setters

### Rotating the crank

- click on the top of the crank
- if you click on the side: the lower you click the slower the turn
- press Enter to start a crank-cycle at the most recently used speed

note:

Once a crankcycle is running it can not be stopped.

### Add or Subtract mode

- Click any other part of the crank
- Or use the keyboard commands:
  - A for Add Mode
  - S for Subtract Mode
- As a reminder a red ring is visible under the crankhandle in Subtract mode

### Moving the carriage

- Click on the shaft you would like to position over the unit position
- You can also move the carriage to any of 6 positions by pressing the 1 to 6 keys
  - 1 .. for the units position
  - 2 .. for the tens position
  - 3 .. for the hundreds position
  - and so on
- As a reminder the shafts of the wheels currently over the unit shafts are shown in red

See the little green dots on the wheels? They show the position of the carry-lever push-down-pin on the rear side of the wheel.

### Turns counter reversing lever

The reversing lever controls the way the crank turns are counted.

- Drag the reversing lever up or down
- Or use the keyboard commands:
  - TI for Turns Counter Increment Mode
  - TD for Turns Counter Decrement Mode
- Up is Increment mode
- Down is Decrement

### Clearing the Results and Turn Counter

- Unfold the clearing lever by clicking on any part of it
- Or use the keyboard command:
  - CX for Clearing lever Epand
- Click on the clearing lever to start clearing
- Or use the keyboard commands:
  - CR for Clearing the Results
  - CT for Clearing the Turns Counter
- The clearing lever clears the results section on the side you click on
- There are 8 different hotspots on the clearing lever for 4 different speeds
- The closer to the body you click, the slower the clearing speed
- Click on the plunger to unlock and fold-in the lever prior to storing the Curta in its container
- Or use the keyboard command:
  - CF for Clearing lever Fold in