The Number Field stores a simple number in the value property.

{
     "PO #": {
      "value": "2345",
      "id": "de084048-ba11-45a2-bf29-a46c0108d3c5",
      "name": "PO #",
      "type": "Number"
    }
}

📘

NOTE

The id, name, and type are not necessary when creating or updating a form, they are returned in the JSON of a request for readability.