---
title: "Introduction to Expressions"
url: "https://helpcentre.esayworkmobile.co.uk/en/article/introduction-to-expressions"
language: "en"
last_updated: "2025-06-12T12:44:22.801Z"
---

# Introduction to Expressions

If you're familiar with using Excel formulas, then the you'll know that you're able to reference data in a specific cell or cells, and then apply a function or calculation to produce a result. This concept also exists within WorkMobile whereby you can populate a widget field value such as a text box, number box or calendar for example, with a value derived from another widget field.

In addition to deriving values, you can also dynamically hide and show widgets or make them editable/read-only based upon other values.

The best way to illustrate using expressions is with a very simple example:  
  
**Example**

-   Add two Number items to a form. 
    -   Give the first one the caption *Amount*, and the second one the caption *Times five*.
-   In the second one, add the following expression (note that expressions always have an “=” sign at the start):

```plaintext
=Amount * 5
```

-   Save the form and publish it.
-   Download the form to your mobile device. 
-   Open the form and type *7* into the “Amount” box. You should see *35* appear in the **Times five** box – the result of

There might be a short delay before it updates as the App waits a short time to make sure you’ve finished typing before it starts calculating.  
  
Try changing the value in **Amount**. **Times five** will update accordingly. Try keying a value into **Times five**. Now change **Amount**. You should see that **Times five** no longer updates.

**Tip**

> If the mobile user keys something into the item with the expression, the expression is “overridden” by the keyed information.
> 
> You can prevent the mobile user from over-typing the value in an item by ticking the read only option for that item in the form designer.