Complex sentence: Six of the seven sheikhdoms (Abu Dhabi, Dubai, Sharjah, Ajman, Umm Al Quwain and Fujairah) combined on that date, the seventh, Ras Al Khaimah, joined the federation on 10 February 1972.
Split into simpler sentences: Six of the seven sheikhdoms (Abu Dhabi, Dubai, Sharjah, Ajman, Umm Al Quwain and Fujairah) combined on that date. The seventh, Ras Al Khaimah, joined the federation on 10 February 1972.