A more thorough explanation:

Pondere, numero, et mensura (pronounced pon-dər-ee, noo-muh-roh, et men-soor-uh) is a Latin phrase that means "by weight, number, and measure." This phrase is used in reference to methods for determining fungibles.

Fungibles are things that can be easily replaced by something else of equal value, such as money, corn, or wine. The phrase ponder, numero, et mensura is used to determine whether a certain subject falls within the class of fungibles. This class includes all those things which perish in the using and which can be estimated generally by weight, number, and measure.

For example, if you want to buy a bag of corn, you would use ponder, numero, et mensura to determine the quantity and quality of the corn. You would weigh the corn to determine the weight, count the number of bags to determine the number, and measure the volume of the corn to determine the measure.

Another example is when you want to buy a bottle of wine. You would use ponder, numero, et mensura to determine the quality and quantity of the wine. You would weigh the bottle to determine the weight, count the number of bottles to determine the number, and measure the volume of the wine to determine the measure.

These examples illustrate how ponder, numero, et mensura is used to determine the quantity and quality of fungibles. By using these methods, you can ensure that you are getting what you paid for and that the product is of good quality.