Computer algebra systems can manipulate symbolic equations, unlike calculators which only handle numbers. While capabilities vary, the core purpose is symbolic equation manipulation. Such systems include tools for graphing, user-defined procedures, and flexible tools for mathematicians. They can simplify expressions, factor polynomials, solve systems of equations, find limits, integrate and differentiate equations symbolically. Early critics doubted computers' ability to handle algebra, but software has proven capable of more operations than humans. Systems store equations in data structures and reference functions to manipulate different variable expressions as rational functions. Common tasks include simplifying expressions and comparing equality.