@jordon There seems to be some IDE issues recently where even number type fields will give this error. It still should work when you run it even though the code gives an error. If it happens when you actually run it you can check to make sure the input is of type number. If it is you can always change the data type of a variable. So you could do something like
let totalStr = totalPrice.toString()
$w(‘#input4’).value = totalStr
keep in mind though that if the input is string typed if you need to do any math with it later you will have to change it back to a number.