Why do we use variables, and what is the significance of using them in expressions and equations?

Question

anonymous · Answer

Variables are used to show that any possible number could go in it's place, but when other numbers are added to that expression or equation, the variable then stands for a certain number that you have to figure out. Numbers go on forever and ever and sometimes people don't know what number should go where in an expression or equation so they use something to hold it's place, a.k.a. a variable. After all the numbers in the expression or equation are added, you can use an algebraic technique to figure out what the variable is and solve the problem that way.