This is a demo of Dynamic Algebra i.e. "doing algebraic calculations on a computer by direct manipulation". You can click in some operator to compute it: 1+11 + 1 You can click in some variables to replace it: x+xx + x Some more examples: x×xx \times x 2\sqrt{2} -b+b2-4×a×c2×a\frac{-b+\sqrt{b^2 - 4 \times a \times c}}{2 \times a}