What are the historical origins of using letters to represent unknown quantities?

We examined how symbols—specifically variables versus numbers—and students' algebraic knowledge impacted seventh graders' problem-solving strategies ... Additional information about Math 015SP, a course designed to yield a deeper understanding of single variable calculus 1 that must be taken concurrently with ... Many students think all variables are letters that stand for numbers. Yet the values a variable takes are not always numbers, even in high school mathematics. What is a Variable in Algebra? A variable is a placeholder for an unknown quantity. In math, variables are used to find general equations and then later ... In mathematics, a variable (from Latin variabilis 'changeable') is a symbol, typically a letter, that refers to an unspecified mathematical object. ... One says ... Expressions and variables ... An algebraic expression comprises both numbers and variables together with at least one arithmetic operation. ... To evaluate an ... Jun 13, 2022 ... In math, a variable is a symbol (often just a single letter like “x”) that stands in for an unknown numerical value in an equation. In computer ... When we solved a system by substitution, we started with two equations and two variables and reduced it to one equation with one variable. This is what we'll do ... Dec 21, 2016 ... Onshape supports all kinds of math in variables, other feature parameters, and dimensions (see https://cad.onshape.com/help/#numeric-fields.htm) Third quarter of honors integrated linear algebra/multivariable calculus sequence for well-prepared students. Topics include change of variables formula, ...