for(key in itemReplenishResults){
    log.debug("Single Data", JSON.stringify(itemReplenishResults[key]));
    var thisNumber = Number(itemReplenishResults[key].getValue("formulanumeric_1"))
}

{
    "recordType": "inventoryitem",
    "id": "2131",
    "values": {
        "itemid": "ITEMCODE",
        "displayname": "DISPLAYNAME",
        "salesdescription": "SALESDESCRIPTION",
        "type": [
            {
                "value": "InvtPart",
                "text": "Inventory Item"
            }
        ],
        "location": [],
        "locationquantityonhand": "",
        "locationreorderpoint": "0",
        "locationpreferredstocklevel": "1",
        "formulatext": "Yes",
        "formulanumeric": "1",
        "locationquantityonorder": "",
        "formulanumeric_1": "1",
        "formulatext_1": "Yes"
    }
}