> For the complete documentation index, see [llms.txt](https://mobsted-2.gitbook.io/knowledge-base/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mobsted-2.gitbook.io/knowledge-base/basics/introduction/use_math_formulas.md).

# Use MathJS formulas

Formulas are used to perform mathematical operations within app. Mobsted platform supports all arithmenical functions and all [MathJS](http://mathjs.org/docs/index.html) formulas.

Use[ Hashtags](/knowledge-base/references/intro-placeholder/hashtags.md) to access data from any part of platform and build math expressions with it.

**Example:**

```
=(  #hashtag1# + #hashtag2# )=
```

OR

```
  =( 3 + #hashtag2# )=
```

**Use case:**

In the example below we can see that the sum of two fields is dynamically updated when we enter the new value to the one of the inputs.![User formulas to perform mathematical operations within the Mobsted SaaS PWA Mobile App Builder.](https://storage.googleapis.com/helpdocs-assets/jyme83anlw/articles/97u2lh1vjo/1549346354540/ezgif-com-video-to-gif-1.gif)

#### \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

#### AVAILABLE FORMULAS

| **Action**        | **Example**                                                   |
| ----------------- | ------------------------------------------------------------- |
| SUM / Multiply    | =( #hashtag1# + #hashtag2# )= / =( 5 \* 2 )=                  |
| Subtract / Divide | =( #hashtag1# - #hashtag2# )= / =( 6 / 2 )=                   |
| Modulus           | =( #hashtag1# % #hashtag2# )=                                 |
| Exponentiation    | =( #hashtag1# - #hashtag2# )= ^ =( #hashtag1# / #hashtag2# )= |
| Square root       | =( sqrt(#hashtag1#) )=                                        |
| Factorial         | =( #hashtag1#! )=                                             |

You can check the set up of some of the above functions on screen - **4** **Math expressions & operations** in **Demo App** in your profile.

####

#### MENTIONED ARTICLES

* [Hashtags](/knowledge-base/references/intro-placeholder/hashtags.md)

#### RECOMMENDED ARTICLES

* [Constructor elements](/knowledge-base/references/intro-placeholder/constructor_elements.md)
* [Mathjs library](http://mathjs.org/docs/index.html)