I want to receive a dollar amount in my utterance. So, for example, if I ask Alexa:
Send $100.51 to Kroger.
(pronounced, One hundred dollars and fifty one cents) I want to receive the value 100.51 in a proper slot. 
I have tried searching and I defined my utterance slots like this:
"slots": [
    {
        "name": "Amount",
        "type": "AMAZON.NUMBER"
    } 
]
But on JSON input I only get this result:
"slots": {
    "Amount": {
        "name": "Amount",
        "value": "?"
    }
}
How can I make Alexa accepts currency values?