Introduction:
An essay is a piece of writing that presents a writer's perspective or argument on a specific topic. There are several types of essays, each with its own purpose and structure. In this question, we are asked to identify the type of essay that is NOT part of the given options.

Narrative Essay:
A narrative essay tells a story or recounts an event. It typically includes characters, a plot, and a setting. The purpose of a narrative essay is to engage the reader and convey a personal experience or point of view. It often includes descriptive language and sensory details to create a vivid and engaging narrative.

Descriptive Essay:
A descriptive essay aims to provide a detailed description of a person, place, object, or event. It uses sensory details and figurative language to paint a picture in the reader's mind. The goal of a descriptive essay is to evoke emotions and create a sensory experience for the reader.

Math Essay:
Mathematics essays are less common than other types of essays, but they do exist. A math essay typically explores a mathematical concept, theory, or problem. It may include explanations, proofs, and examples to support the writer's argument. Math essays require a strong understanding of mathematical concepts and the ability to communicate them effectively.

Persuasive Essay:
A persuasive essay aims to convince the reader to adopt a particular point of view or take a specific action. It presents arguments and evidence to support the writer's position. Persuasive essays often include a clear thesis statement, logical reasoning, and emotional appeals. The purpose is to persuade the reader to agree with the writer's perspective.

Conclusion:
Based on the given options, the type of essay that is NOT included is "Math." While math essays do exist, they are not as common as narrative, descriptive, and persuasive essays. Math essays require a specific focus on mathematical concepts and may not be applicable to all subjects or topics.