Photosynthesis takes Carbon Dioxide, Water, and Sunlight to make Glucose and oxygen, but this glucose is STORED. Cellular respiration takes this glucose and oxygen and converts it to Carbon Dioxide, water, and energy (ATP), so the equations match if you switch them. This process releases the glucose as energy
It is very interesting how photosynthesis and cellular respiration help each other. During photosynthesis, the plant needs carbon dioxide and water-- both of which are released into the air during respiration. And during respiration, the plant needs oxygen and glucose, which are both produced through photosynthesis!
