# Subtract Variable

**Subtract Variable** node is designed to perform subtraction operations on a specified variable and store the result back in the same variable. This node is useful for decreasing values or calculating differences within your workflow.

### Properties Panel

<table data-header-hidden><thead><tr><th width="165"></th><th width="380"></th><th></th></tr></thead><tbody><tr><td><strong>Field</strong></td><td><strong>Description</strong></td><td><strong>Required</strong></td></tr><tr><td>Node name</td><td><a href="../../../node-name">Node Name</a></td><td>true</td></tr><tr><td>Variable Name</td><td>The name of the variable from which the value will be subtracted.</td><td>true</td></tr><tr><td>Value</td><td>The value to subtract from the variable.</td><td>true</td></tr></tbody></table>

### Usage

1. Specify the name of the variable from which you want to subtract.
2. Enter the subtrahend (the value to be subtracted from the variable).

### Behaviour

* The node will retrieve the current value of the specified variable.
* It will then subtract the provided value from this variable.
* The result of the subtraction will be stored back in the same variable, overwriting its previous value.
* If the variable doesn't exist, it'll raise an error.

### Returns

The node updates the value of the specified variable with the result of the subtraction. You can access this updated value using Magical Autocomplete (e.g., `$.variables.<variable_name>`) in any node below this node.

### Example

Let's say you want to apply a $5 discount to a `price`. You already have a variable `price`:

1. Set Variable name to `$.variables.price`
2. Set Value to `5`

If it exists and `price` was `20`, it will now be `15`.

### Best Practices

* Ensure that the variable you're subtracting from contains a numeric value to avoid type conversion errors.
* Be aware of the order of subtraction. This node subtracts the provided value from the variable, not the other way around.
* Ensure that the variable is initialized earlier