52 grams of cereal equals how many cups?

"Cups" is a measurement of volume, or "how much cereal occupies this space?" Grams is a measurement of weight. Rice crispies, for example, are puffed rice. There is plenty of air in them making them a lightweight cereal. Grape nuts are a solid dense cereal, making them heavier than rice crispies. There is no accurate answer to this question.