Elements of Algebra is a mathematics textbook by mathematician Leonhar Euler, originally published circa 1765. His Elements of Algebra is one of the first books to set out algebra in the modern form we would recognize today. However, it is sufficiently different from most modern approaches to the subject to be interesting for contemporary readers. Indeed, the choices made for setting out the curriculum, and the details of the techniques Euler employs, may surprise even experts. It is also the only mathematical work of Euler which is genuinely accessible to all. The work opens with a discussion of the nature of numbers and the signs + and -, before systematically developing algebra to a point at which polynomial equations of the fourth degree can be solved, first by an exact formula and then approximately. The Elements of Algebra contains many important early results in mathematical analysis; for example, it contains Euler's original proof of Fermat's Last Theorem for the special case of n = 3.