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_76049 ( "Round" text, "Main date" text, "Number of fixtures" real, "Clubs" text, "New entries this round" text )

### Question ###
What is the sum of Number of fixtures when the rounds shows quarter-finals?

### Accurate SQL ###

SELECT SUM("Number of fixtures") FROM table_76049 WHERE "Round" = 'quarter-finals'