is it possible to use JSON Numeric aggregation functions in API gateway map

As the subject says, I am looking if it is possible to use JSON Numeric aggregation functions in API gateway mapping templates?
I have the below template and I would want to add the "ttl" column as a future date.
{
"TableName": "api",
"Item": {
"ingestId": {
"S": "$context.requestId"
},
"ttl": {
"N": "$context.requestTimeEpoch"
}
}
}

So I wanted to try the sum() function of the request Epoch time and some number to get a future date as the result.
Any suggestions and inputs are welcome.