Mathematics is everywhere and is used in many everyday activities. It took many years for many people to develop the mathematics we use today. Mathematicians are some of the most important people in the world because they developed theorems that advanced humanity and ultimately helped make the world what it is today. Leonhard Euler is a distinguished mathematician with many incredible contributions to the world of mathematics and much more. His contributions are so widely used that mathematics would not be the same without them. Leonhard Euler was born on April 15, 1707 to pastor Paul Euler and grew up with two younger sisters in Basel, Switzerland. By the age of thirteen, Euler had already begun taking classes at the University of Basel and received his master's degree in 1723. Euler's father urged him to continue his education by studying theology. Euler complied, but insisted on devoting all his free time to studying mathematics. Euler's teacher, Johann Bernoulli, was very impressed by the articles Euler wrote on the reverse trajectory and appreciated him as a student. In 1727, at the urging of Bernoulli, Euler applied to join the St. Petersburg Academy of Sciences, but due to the financial instability of the academy, Euler decided to join the Russian navy for three years to secure a regular income. After a few years, Euler's financial situation improved and he was able to marry Katharina Gsell and have fifteen children with her. Unfortunately, only three boys and two girls survived. In 1741, Euler worked at the Berlin Academy of Sciences, heading the Berlin Observatory, while also mentoring the nieces of King Frederick II of Prussia. Regardless of his age, Leonhard Euler was always very interested in the world of mathematics......middle of paper......graphy. February 11, 2014. Editorial team, Paramon's. Essential Atlas of Mathematics. Barcelona, ​​2003. Paper book. Gautschi, Walter. Leonhard Euler: his life, the man and his works. Zurich, 2008. Ebook. Grinstein, Louise. Encyclopedia of Mathematics Education. New York, 2001. Encyclopedia. Hoffman, Mike. “Mike Hoffman Home Page.” December 9, 2013. . Article. December 9, 2013. O'Connor, JJ and EF Robertson. “Leonhard Euler.” September 1998. http://www-history.mcs.st-and.ac.uk/Biographies/Euler.html. Biography. February 9, 2014. Patterson, Simon. “The Euler International Mathematical Institute.” and http://www.pdmi.ras.ru/EIMI/EulerBio.html. Article. February 8, 2014. Stocksill, John. “Leonhard Euler (pronounced “Oiler”) 1707-1783.” 2000. . Article. December 10 2013.