# Arithmetic operators

[Read this page in HTML](https://www.scopedb.io/docs/reference/commands/query-operators/arithmetic)

Arithmetic operators calculate values from numeric expressions. `+` and `-` also support timestamps and intervals.

Numeric inputs use `int`, `uint`, or `float`. The supported date and time operations are:

| Left type   | Operator | Right type  | Return type |
| ----------- | -------- | ----------- | ----------- |
| `timestamp` | `+`      | `interval`  | `timestamp` |
| `interval`  | `+`      | `timestamp` | `timestamp` |
| `interval`  | `+`      | `interval`  | `interval`  |
| `timestamp` | `-`      | `interval`  | `timestamp` |
| `timestamp` | `-`      | `timestamp` | `interval`  |

## List of arithmetic operators

| Operator | Arity  | Syntax  | Description                                                                                                              |
| -------- | ------ | ------- | ------------------------------------------------------------------------------------------------------------------------ |
| `-`      | unary  | `-a`    | Negates the input numeric expression.                                                                                    |
| `+`      | binary | `a + b` | Adds two numeric expressions (`a` and `b`).                                                                              |
| `-`      | binary | `a - b` | Subtracts one numeric expression (`b`) from another (`a`).                                                               |
| `*`      | binary | `a * b` | Multiplies two numeric expressions (`a` and `b`).                                                                        |
| `/`      | binary | `a / b` | Divides `a` by `b`, returning `float`. Nonzero values divided by zero produce a signed infinity; `0 / 0` produces `NaN`. |
| `%`      | binary | `a % b` | Computes the modulo of numeric expression `a` by `b`.                                                                    |

## Examples

Calculate the completion rate and number of unfinished checkouts for each channel:

```scopeql
VALUES ('web', 80, 23), ('mobile', 60, 17)
SELECT $0 AS channel, $1 AS checkouts, $2 AS completed
SELECT
    channel,
    checkouts - completed AS unfinished,
    round(completed / checkouts * 1000.0) / 10.0 AS completion_pct
```

```text
+---------+------------+----------------+
| channel | unfinished | completion_pct |
+---------+------------+----------------+
| web     | 57         | 28.8           |
| mobile  | 43         | 28.3           |
+---------+------------+----------------+
```

Division returns `float` even when both counts are integers. The multiplication and rounding express the ratio as a percentage with one decimal place.