The bulk cereals and bagged cereals weighed by pounds in supermarkets mainly differ in the following three aspects:

1. Ingredients and nutritional value: Bulk cereals are mainly raw oats, while bagged cereals are mainly raw oats. Packed oats are processed instant oats or flavored oats. In terms of nutritional value, bulk cereals retain relatively more comprehensive nutrients because they are not processed.

2. How to eat: Bulk cereals need to be cooked before they can be eaten, while bagged cereals only need to be brewed with hot water and some products only need to be simply mixed.

3. Price: Generally speaking, the price of bulk cereal is relatively lower than that of bagged cereal because the packaging and sales form of bulk cereal is relatively simple.

In general, the main differences between bulk cereals and bagged cereals in supermarkets are their ingredients, nutritional value, consumption methods and prices.