Year 90 (XC) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Nerva (or, less frequently, year 843 Ab urbe condita). The denomination 90 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Turkey went from six (2+4) to seven digits (3+4) local phone numbers c.1988, at which time Ankara went from 41 to 4. There used to be more than 5000 local area codes of varying lengths (one to five digits) with correspondingly varying local number lengths (seven to three digits).

Year 90 (XC) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Nerva (or, less frequently, year 843 Ab urbe condita). The denomination 90 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Turkey went from six (2+4) to seven digits (3+4) local phone numbers c.1988, at which time Ankara went from 41 to 4. There used to be more than 5000 local area codes of varying lengths (one to five digits) with correspondingly varying local number lengths (seven to three digits).