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Did you know?
The horizontal fraction bar was introduced by the Arabs.
Did you know?
On average, the stomach produces 2 L of hydrochloric acid per day.
Did you know?
Bacteria have been found alive in a lake buried one half mile under ice in Antarctica.
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Vaccines prevent between 2.5 and 4 million deaths every year.
Did you know?
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.