It is not necessary to cite all the facts you may want to use in your paper.

Common knowledge or well-established facts do not have to be cited. For example:

• A day is divided into 24 hours.
• Paris is the capital of France.
• Golda Meir was the first female prime minister of Israel.
• The distance of the moon from the Earth is 385,000 kilometers (240,000 miles).
• The Hawaiian Islands were formed by underwater volcanic activity.

University of Hawaii Students Explain Common Knowledge!