Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_201_24 ( id number, "episode number" number, "original airdate" text, "title" text, "disc" number, "description" text )

### Question ###
how many episodes are in series 7 -lrb- 1983 -rrb- ?

### Accurate SQL ###

SELECT COUNT("episode number") FROM table_201_24 WHERE "original airdate" = 1983