# {math}

`{math}` allows the template designer to do math equations in the
template.

## Attributes

| Attribute Name | Required | Description                                      |
|----------------|----------|--------------------------------------------------|
| equation       | Yes      | The equation to execute                          |
| format         | No       | The format of the result (sprintf)               |
| var            | Yes      | Equation variable value                          |
| assign         | No       | Template variable the output will be assigned to |
| \[var \...\]   | Yes      | Equation variable value                          |

-   Any numeric template variables may be used in the equations, and the
    result is printed in place of the tag.

-   The variables used in the equation are passed as parameters, which
    can be template variables or static values.

-   +, -, /, \*, abs, ceil, cos, exp, floor, log, log10, max, min, pi,
    pow, rand, round, sin, sqrt, srans and tan are all valid operators.
    Check the PHP documentation for further information on these
    [math](https://www.php.net/eval) functions.

-   If you supply the `assign` attribute, the output of the `{math}`
    function will be assigned to this template variable instead of being
    output to the template.

> **Note**
>
> `{math}` is an expensive function in performance due to its use of the
> php [`eval()`](https://www.php.net/eval) function. Doing the math in PHP
> is much more efficient, so whenever possible do the math calculations
> in the script and [`assign()`](../../programmers/api-functions/api-assign.md) the results to the
> template. Definitely avoid repetitive `{math}` function calls, eg
> within [`{section}`](../language-builtin-functions/language-function-section.md) loops.

## Examples

**Example 1**
```smarty

{* $height=4, $width=5 *}

{math equation="x + y" x=$height y=$width}
```
      
The above example will output:

```
9
```


**Example 2**

```smarty
{* $row_height = 10, $row_width = 20, #col_div# = 2, assigned in template *}

{math equation="height * width / division"
    height=$row_height
    width=$row_width
    division=#col_div#}
```

The above example will output:

```
100
```
      
**Example 3**

```smarty
{* you can use parenthesis *}

{math equation="(( x + y ) / z )" x=2 y=10 z=2}
```

The above example will output:

```
6
```

**Example 4**

```smarty
{* you can supply a format parameter in sprintf format *}

{math equation="x + y" x=4.4444 y=5.0000 format="%.2f"}
```     
      
The above example will output:
```
9.44
```