The three cards on the left are input cards. From the top, Unit price is shown as a number field, Quantity as ± buttons and Discount as a slider. Total on the right is calculated from the three, so changing any of them changes the total.
Pressing + on Quantity once makes it 4 items, and the total becomes $144. With Quantity back at 3, moving the Discount slider to 20% gives a total of $96.
Placing an input card
The "Add a card" button at the top left of the screen (a square with + in it) opens the list of cards. Pressing "A number to play with" (Input) in that list places an input card.
A new input card is shown as a number field and holds 0. Switched to a slider, its range is 0 to 100 and its step is 1. A name typed in the name field at the top of the card, such as "Unit price", is also what appears in other cards' formulas.
Switching the display
The top of an input card has a "● Record" button and a menu for the display style. The menu offers "Number field", "± buttons" and "Slider". Switching keeps the card's value; only the way it is changed and the way it looks are different.
- Number field — a large field to type the number into. Decimals and negative numbers work too.
- ± buttons — each press of − or + changes the value by one step. The field between them can also be typed into.
- Slider — the knob is dragged left or right. The small fields on either side are the minimum (left) and the maximum (right).
With Discount back at 10% and the Unit price card switched to "± buttons", each press of + adds $10. One press makes it $50, and the total becomes $135.
Minimum, maximum and step
The minimum and maximum set how far the slider's knob can move. Discount on Board 1 runs from 0 to 50% in steps of 5, so the knob stops at 0, 5, 10 and so on up to 50. The ± buttons use the same step: on Board 1 that is 1 for Quantity and 10 for Unit price.
The fields on either side of a slider change its minimum and maximum. A minimum larger than the maximum moves the maximum to the minimum plus 100. An input card has no field for changing the step.
Values outside the range
The minimum and maximum only limit the knob. A value typed into the number field, or reached with the ± buttons, is used as it is, even outside the range.
With Unit price back at $40, switching Discount to "Number field" and typing 60 makes the discount 60%. The total becomes $48.
Switched back to "Slider", the card still shows 60% and the knob sits at the right end. Moving the knob brings the value back into the 0 to 50% range. Lowering the maximum below the current value leaves the value as it is, too. The ± buttons do not stop at the range either: pressing − at 0 gives −1.
For a value beyond the slider's range, you can switch to the number field and type it, or widen the maximum in the right-hand field.
The boards in the triangle area article use a separate "Slider" card instead of an input card. It is an older card that the "Add a card" list no longer offers. That card has a "Step" field, so its step can be changed, and lowering its maximum below the current value brings the value down to the maximum.
Units and decimal places
An input card shows its unit ($, items, % and so on) next to the value. The unit is only a label and plays no part in the calculation: Discount on Board 1 is the number 10, and the formula divides it by 100.
The unit and decimal places of a calculation card are chosen in the calculator at the bottom of the screen.
- When the calculator is folded away, "Expand keyboard" (the upward arrow) opens it.
- Selecting a calculation card puts its name and formula into the calculator's display.
- The "Result settings" button at the lower left of the display shows the "Unit" and "Decimal places" choices.
- Pressing "Done" after choosing applies them to the card.
Units include "None", "$", "%" and "kg"; "Other" lets you write your own, such as "$/month". Decimal places are "Auto" or 0 to 4. These settings apply to calculation cards; an input card's unit does not change here.