The new Formidable Pro Address field doesn’t allow single items, like Street or City, to be used in calculations without writing custom codes.
This is a simple workaround, which copy the single items in multiple hidden fields that can be used in any field calculations.
1. Set the key value of your Address field to "addr_full"

2. Create 6 new Hidden Fields
NAME KEY
Street1 addr_street1
Street2 addr_street2
City addr_city
ZIP addr_zip
State addr_state
Country addr_country

3. Insert this Javascript code in Form Settings/Customize HTML/After Fields
<script type="text/javascript">
jQuery(document).ready(function($){
$('#field_addr_full_line1, #field_addr_full_line2, #field_addr_full_zip, #field_addr_full_city, #field_addr_full_state, #field_addr_full_country').change(function(){
$("#field_addr_street1").val($("#field_addr_full_line1").val())
$("#field_addr_street2").val($("#field_addr_full_line2").val())
$("#field_addr_zip").val($("#field_addr_full_zip").val())
$("#field_addr_city").val($("#field_addr_full_city").val())
$("#field_addr_state").val($("#field_addr_full_state").val())
$("#field_addr_country").val($("#field_addr_full_country").val())
});
});
</script>

4. Done!
Now everytime users insert text in any Address field, all single address items will be copied in the corresponding hidden fields, ready to be used for other functions and field calculations.