Which memory type involves recalling a simple math equation from memory effortlessly?

The correct choice pertains to explicit (declarative) memory, which is responsible for the conscious retrieval of information that can be verbally described. Explicit memory encompasses both episodic memories, which involve personal experiences, and semantic memories, which include general knowledge such as facts and concepts.

In the context of recalling a simple math equation, such as 2 + 2, this process requires the active retrieval of knowledge that one has learned and stored previously. For example, you may have been taught basic math in school, allowing you to consciously remember that 2 + 2 equals 4. This recall is an act of deliberate remembrance, which exemplifies the nature of explicit memory.

The other types of memory listed do not fit this scenario as accurately. Implicit memory refers to skills and procedures that one can perform without conscious recall, such as riding a bike. Short-term memory typically involves holding onto information temporarily for immediate use, while long-term memory refers to stored information that has been consolidated over time. However, since the question highlights the effortless recall of a simple math equation, it aligns best with explicit memory, where the retrieval of factual knowledge is required.