How to check the freshness of eggs?

1. Pour water into a glass and dissolve one tablespoon of salt. 2. Gently place an egg into the glass of saltwater. 3. Observe the egg's behavior: If the egg lies horizontally at the bottom, it is up to 6 days old. If the egg is lifted upwards with the blunt end of the egg, it is 7-10 days old. If the egg takes an upright position, it is 11-14 days old. If the egg floats, it is about 25 days old and cannot be eaten.