6 CO2 + 6 H2O + light ? C6H12O6 + 6 O2
Carbon Dioxide + Water + Light energy ? Glucose + Oxygen
They take in carbon dioxide, water and light energy, do their crazy stuff (did an enourmous study on exactly how these reactions work, and it's quite a process) and the result is glucose, which they can use, and oxygen which is great for us.