CREATE TABLE table_19048 ("SUBJECT" TEXT, "FRESHMAN  ( Grade 7 ) " TEXT, "SOPHOMORE  ( Grade 8 ) " TEXT, "JUNIOR  ( 3rd Year ) " TEXT, "SENIOR  ( 4th Year ) " TEXT)

How many classes between senior and junior year for world history
SELECT COUNT("SENIOR (4th Year)") FROM table_19048 WHERE "JUNIOR (3rd Year)" = 'World History'
SELECT COUNT("SENIOR (4th Year)") FROM "table_19048" WHERE "JUNIOR (3rd Year)" = 'World History'