Why do we still learn algebra when calculators exist?

A calculator can execute a computation, but it cannot decide what the computation means. Algebra teaches you how to: - turn a situation into equations, - see which quantities depend on which, - simplify a problem before computing, - check whether an answer is reasonable, - understand formulas instead of only pressing buttons. For example, a calculator can solve $$2x+5=17.$$ But algebra is what tells you why subtracting 5 from both sides preserves the solution, and why the answer should be $$x=6.$$ The real value is not hand-calculating forever. The value is learning the structure behind the calculation, so technology becomes a tool rather than a black box.