How many child sultan of Brunei?

There are seven children of the Sultan of Brunei, Hassanal Bolkiah, who currently reign since 1967. Their names and titles are:

1) Princess Rashidah Bolkiah (born: 1969) - Princess of Brunei

2) Prince Haji Al-Muhtadee Billah Bolkiah (born: 1974) - Crown Prince and heir apparent to the Sultan of Brunei

3) Prince Haji Abdul Azim Bolkiah (born: 1982) - Prince of Brunei

4) Princess Hajah Majeedah Nuurul Bolkiah (born: 1985) - Princess of Brunei

5) Prince Haji Abdul Malik Bolkiah (born: 1987) - Prince of Brunei

6) Princess Hajah Hafizah Sururul Bolkiah (born: 1988) - Princess of Brunei

7) Prince Haji Abdul Mateen Bolkiah (born: 1991) - Prince of Brunei