CREATE TABLE table_203_568 (id NUMBER, "town/village" CLOB, "population" NUMBER, "postal code" CLOB, "municipality" CLOB, "island" CLOB, "location" CLOB)

how much greater is the population of argir than glyvrar ?
SELECT (SELECT "population" FROM table_203_568 WHERE "town/village" = 'argir') - (SELECT "population" FROM table_203_568 WHERE "town/village" = 'glyvrar')
SELECT (SELECT "population" FROM "table_203_568" WHERE "town/village" = 'argir') - (SELECT "population" FROM "table_203_568" WHERE "town/village" = 'glyvrar')