# Quantity

Source: https://developer.avalara.com/avatax-dm-combined-erp/sales-tax-badge/transactions/cert-quantity/

# Quantity

**Element type: Required**

**Endpoints/models used:** [LineItemModel](https://developer.avalara.com/api-reference/avatax/rest/v2/models/LineItemModel/)

Your UI must include a method for allowing users to specify the quantity of an item that is passed to AvaTax. Items quantities are specified using the`quantity` field on the [LineItemModel](https://developer.avalara.com/api-reference/avatax/rest/v2/models/LineItemModel/).

This field should be optional for users. If a user does not provide a`quantity`, the AvaTax API will assume the quantity to be 1.

```
{    "lines": [        {            "number": "1",            "quantity": 1,            "amount": 100,            "taxCode": "PS081282",            "itemCode": "Y0001",            "description": "Yarn"        }    ],  ...}
```

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