Algebra (from Arabic: الجبر‎, transliterated "al-jabr", meaning "reunion of broken parts") is a part of mathematics. It uses variables to represent a value that is not yet known or can be replaced with any value. When an equals sign (=) is used, this is called an equation. A very simple equation using a variable is: \displaystyle{ 2 + 3 = x }. In this example, \displaystyle{ x = 5 }, or it could also be said that "\displaystyle{ x } equals five". This is called solving for \displaystyle{ x }.