The fact that a negative times a negative equals a positive can be proven mathematically using algebraic manipulation. Specifically, it can be proven using the equation x = (a)(b) + (-a)(b) + (-a)(-b), where a and b are ... More »

A negative number divided by a negative number always yields a positive number. For instance, -4 / -2 = 2. In other words, there are two -2s in -4. More »

Algebra 1 focuses on the manipulation of equations, inequalities, relations and functions, exponents and monomials, and it introduces the concept of polynomials. One of the key skills learned in Algebra 1 is the ability ... More »

According to Math Open Reference, pi is a mathematical constant obtained by dividing the circumference of any circle by its diameter. Pi is about 22/7 or 3.142. However, no one knows its exact value. More »

A turnaround fact in math is an addition or multiplication fact for which, if the addends or factors are reversed, the answer is still the same. For example, two plus three equals five, and three plus two equals five. On... More »

One interesting fact about algebra is that the name originated from the Arabic word "al-jabr." Its history began in ancient Egypt and Babylon. The Persian mathematician Muhammed ibn Musa Al-Khwarizmi is credited as one o... More »

Cos(2pi) is equal to 1. The cosine function, cos(x), oscillates between 1 and -1 with a period of 2pi as x varies. By definition, cos(0) = 1, and the periodicity of the function means the cosine of all multiples of 2pi (... More »