The Free High School Science Texts: Math - Grade 10
According to the website, "Mathematics is a language, specifically it is the language of Science. Like any language, mathe- matics has letters (known as numbers) that are used to make up words (known as expressions), and sentences (known as equations). The punctuation marks of mathematics are the differ- ent signs and symbols that are used, for example, the plus sign (+), the minus sign (-), the multiplication sign (×), the equals sign (=) and so on. There are also rules that explain how the numbers should be used together with the signs to make up equations that express some meaning."