6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Let's break down the formula:

* 6CO₂: This represents six molecules of carbon dioxide (CO₂). Each CO₂ molecule contains one carbon atom. So, there are 6 x 1 = 6 carbon atoms in the reactants.

* C₆H₁₂O₆: This represents one molecule of glucose (C₆H₁₂O₆). This molecule contains six carbon atoms.

Therefore, there are 6 carbon atoms in the reactants and 6 carbon atoms in the product of the photosynthesis reaction.