1. Each year in the United States, there are approximately six million pregnancies. This means that at any one time, about 4% of women in the United States are pregnant.

2. About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.

3. Approximately 500,000 babies are born each year in the United States to teenage mothers.

4. The largest baby ever born weighed more than 23 pounds but died just 11 hours after his birth in 1879. The largest surviving baby was born in October 2009 in Sumatra, Indonesia, and weighed an astounding 19.2 pounds at birth.

5. Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the Un ...

1)  Roman Numeral IV

Although the Roman numeral for the number 4 has always been taught to have been "IV," according to historians, the ancient Romans probably used "IIII" most of the time. This is partially backed up by the fact that early grandfather clocks displayed IIII for the number 4 instead of IV. Early clockmakers apparently thought that the IIII balanced out the VIII (used for the number 8) on the clock face and that it just looked better.

2)  Base 60

The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."

3)  Fraction Bar

The Romans did not use numerals to indicate fractions but instead used words to indicate parts of a whole. It wasn't until later in h ...