Give us a call (917) 722-0677

You can excel with Caddell!

SAT Function & Purpose: Lesson, Practice Problems & Video Explanations

By Glyn Caddell, BSME · Author of Digital SAT Math Secrets · Tutoring since 2008 — Updated August 18, 2026

Digital SAT Function & Purpose

Function & purpose questions ask students to determine why the author included a certain sentence, detail, example, or paragraph. Students need to understand how that part of the text contributes to the author’s overall point. Function & purpose questions appear on approximately 8.0% of the Digital SAT Reading & Writing section. These questions fall under Craft and Structure according to the College Board categories.

Table of Contents

Function & Purpose Lesson

The lesson covers the types of function & purpose questions that show up on the Digital SAT, how to approach the questions, and an example of an SAT question.

What Do Function & Purpose Questions Look Like?

These questions ask what function/purpose a certain sentence, word, mention, etc. serves. Some of them can be easily spotted because the text will include an underlined sentence.

Here are some examples of Function & Purpose questions from the Digital SAT.

  • Which choice best states the main purpose of the text?
  • Which choice best describes the function of the underlined sentence in the text as a whole?
  • Which choice best describes the function of the underlined portion in the text as a whole?
  • Which choice best describes the function of the second sentence in the overall structure of the text?

How to Answer Function & Purpose Questions Correctly

  1. Function & purpose questions ask you why an entire text was written or why sentences, a sentence, or a part of a sentence was included. The text in question will be underlined, unless the question asks about the entire text.
  2. Keep in mind the main topic of the passage when thinking about the purpose of the underlined text.
  3. Remember that the question doesn’t ask about the underlined text itself; it asks what purpose it serves in the passage. Put yourself in the author’s shoes and think about why you would include that text.

What Are Common Functions & Purposes on the Digital SAT?

There are common functions & purposes the included text serves on the Digital SAT.

  • Continue a discussion
  • Illustrate/provide an example
  • Explain
  • Define a phrase or term
  • Compare an idea with another
  • Speculate
  • Emphasize an idea or statement
  • Draw a conclusion
  • Show contrast
  • Question the validity of something

Example

The following text is adapted from W. E. B. Du Bois’s The Souls of Black Folk (1903).

Du Bois argued that education should do more than prepare individuals for employment. In his view, true education cultivated judgment, curiosity, and a deeper understanding of society. Without those qualities, technical training alone could produce skilled workers but not fully informed citizens.

Which choice best states the function of the underlined sentence in the text as a whole?

A) It provides an example illustrating the economic value of education.
B) It presents a qualification that limits the importance of technical training.
C) It introduces a criticism of workers who lack formal schooling.
D) It explains why Du Bois believed employment opportunities were unimportant.

Video Explanation

Text Explanation

Answer: B

The passage argues that education should develop intellectual and civic qualities in addition to job skills. The underlined sentence qualifies the value of technical training by suggesting that, on its own, it is insufficient. Choice A is incorrect because the sentence does not focus on economic value. Choice C misrepresents the tone of the passage, and choice D is too extreme because the text never suggests employment is unimportant.

Practice Problems with Video Explanations

Here is a set of practice Digital SAT function & purpose practice problems. After selecting an answer, press “See Answer” to see the correct answer and a video explanation showing how to properly solve the questions. At the end of the set, after you press “Submit”, you’ll be able to see all of the questions, answers, and video explanations to review.

For more practice like this, enroll in our on-demand SAT prep course here: https://caddellprep.com/sat/prep/on-demand/

1. The following text is adapted from Frances Hodgson Burnett’s The Secret Garden (1911). Mary has just begun exploring the grounds of Misselthwaite Manor.Mary had never thought the world could contain so many bare, twisting branches and so wide a stretch of gray-brown earth. Yet as she walked farther, she began to hear birds in the hedges and to notice green points pushing up through the soil. What had seemed dead at first now looked as if it were quietly waking.Which choice best states the function of the underlined sentence in the text as a whole?

Question 1 of 5

2. The following text is adapted from an 1873 report by naturalist Anton de Bary about lichens.For many years, lichens were treated as simple plants. De Bary and other researchers, however, observed that a lichen is not a single organism but a partnership between a fungus and an alga. This finding forced botanists to reconsider the way living things were classified.Which choice best states the function of the underlined sentence in the text as a whole?

Question 2 of 5

3. The following text is adapted from Louisa May Alcott’s Little Women (1868). Jo has been asked to behave more formally at a social gathering.Jo tried to sit still and speak softly, but every few minutes she forgot herself and laughed too loudly or answered too quickly. She knew that Aunt March disapproved. Still, the more Jo was expected to act unlike herself, the more impossible the task became.Which choice best states the function of the underlined sentence in the text as a whole?

Question 3 of 5

4. The following text discusses the invention of the stethoscope by René Laennec in 1816.When examining patients, Laennec sometimes found it awkward or impractical to place his ear directly against the chest, which was then a common diagnostic method. Inspired by the way sound travels through wood, he rolled a sheet of paper into a tube and used it to listen to a patient’s heartbeat. From that simple experiment came an instrument that transformed medical practice.Which choice best states the function of the underlined sentence in the text as a whole?

Question 4 of 5

5. The following text is adapted from Kate Chopin’s The Awakening (1899).Edna had gone down to the shore expecting only a brief walk. The sea was quiet, the air warm, and the beach nearly empty. For the first time that day, she felt not restless but attentive, as if the world had paused long enough for her to hear herself think.Which choice best states the function of the underlined sentence in the text as a whole?

Question 5 of 5


 

Related Topics

Main Idea and Inference are topics related to Function & Purpose.

Main Idea

Function & purpose questions are related to main idea questions because students need to understand the overall point of a text before determining the role of a specific part. In main idea questions, students identify the central idea of the passage. In function & purpose questions, students determine how a sentence or detail helps develop that central idea. Therefore, practicing main idea questions can help students improve on function & purpose questions.

Inference

Function & purpose questions are related to inference questions because both require students to make a logical conclusion based on the text. In inference questions, students determine what must be true based on the information provided. In function & purpose questions, students determine why the author included certain information, even when that reason is not stated directly. Therefore, practicing inference questions can help students better understand the reasoning behind function & purpose questions.

All Reading & Writing Topics

All of our reading & writing topics are available here: https://caddellprep.com/sat/reading-writing/ for you to review and improve on your SAT. There are lessons, practice problems, and video explanations for you. If you need more help, try our on-demand SAT course with video lessons, practice tests, and sets of questions for each topic: https://caddellprep.com/sat/prep/on-demand/

Glyn Caddell - Founder of Caddell Prep

Glyn Caddell

Glyn Caddell holds a BS in Mechanical Engineering from NJIT and has been tutoring New York City students since 2008. He founded Caddell Prep in 2012 and is the author of Digital SAT Math Secrets: Lessons & Tricks to Quickly Improve to a Perfect 800 on the Math Test, which contains over 900 practice problems and is used in Caddell Prep’s SAT math classes. He is founding president of the Staten Island Technical High School alumni association and teaches every lesson on this site personally.

Need Help Preparing for the SAT?

Use the only SAT prep course built with an engineer’s approach and taught in a way that students actually understand.

100-point score increase guarantee

Learn More

Take a Free Diagnostic SAT

Discover the 5 Topics That Could Make the Biggest Difference in Your Score.

Take our free diagnostic and receive a personalized assessment showing exactly what to study next.

Click Here