CREATE TABLE table_204_584 (id DECIMAL, "pos" TEXT, "no" DECIMAL, "driver" TEXT, "constructor" TEXT, "laps" DECIMAL, "time/retired" TEXT, "grid" DECIMAL, "points" DECIMAL)

how many fewer laps did carlos pace complete than jochen mass ?
SELECT (SELECT "laps" FROM table_204_584 WHERE "driver" = 'jochen mass') - (SELECT "laps" FROM table_204_584 WHERE "driver" = 'carlos pace')
SELECT (SELECT "laps" FROM "table_204_584" WHERE "driver" = 'jochen mass') - (SELECT "laps" FROM "table_204_584" WHERE "driver" = 'carlos pace')