# Formulas

## Arithmetic

**Card** → **Enable Formula**

## Parentheses (Nested Cards)

Deeper Cards compute before their parent(s). Therefore, Nested Cards act like parentheses. They have an operator unless they are the first formula item.

## Rounding

## Presets

**Card** → **Formula Presets**

To remove a preset, re-click the active preset button.

## Selectors

Formulas use the selected Entry Value.

## Checkboxes

Internally, a Checkbox value is **1** or **0**. This example
multiplies that value by $5.00 (a "Hidden in Previewer" Entry)
using a formula. Effectively, this is a no-code conditional form.

## Alternatives to Formulas

The next document is about integrating JavaScript. Therefore, you can also write formulas like:

function ({ radius }) { return Math.PI * radius.value ** 2 }