What does these prefixes for deca?

It seems you're asking about prefixes related to the word "deca" which is a Greek word meaning "ten". Here's what you need to know about prefixes related to "deca":

* Deca- (pronounced "dek-uh") is a prefix used in the metric system to indicate ten times the base unit.

* For example, a decameter (dam) is 10 meters, a decaliter (dal) is 10 liters, and a decagram (dag) is 10 grams.

* Deci- (pronounced "dess-ee") is a prefix indicating one-tenth of the base unit.

* For example, a decimeter (dm) is 0.1 meters, a deciliter (dl) is 0.1 liters, and a decigram (dg) is 0.1 grams.

Let me know if you want more details about these prefixes or have other questions about the metric system!