Table: jamaican_citizenship_2
Columns: year
numer_of_jamaicans_granted_british_citizenship
naturalisation_by_residence
naturalisation_by_marriage
registration_of_a_minor_child
registration_by_other_means

Question: Tell me the sum of number of jamaicans given british citizenship for 2004 and registration of a minor child more than 640
SQL: SELECT SUM("numer_of_jamaicans_granted_british_citizenship") FROM jamaican_citizenship_2 WHERE "year" = 2004 AND "registration_of_a_minor_child" > 640