# Lesson Notes — The Four Pillars of Computational Thinking

- Link: https://doss.academy/course-1-computer-literacy/unit-14-computational-thinking-problem-solving/lesson-1-the-four-pillars-of-computational-thinking/lesson-notes-c1u14l1/
- Published: 2026-10-19T12:14:03-04:00
- Author: matthew.leffler@jefferson.kyschools.us

Course 1: Computer Literacy / Unit 14: Computational Thinking & Problem Solving /
Lesson 1: The Four Pillars of Computational Thinking

## Lesson overview

Computational thinking is a way of solving problems that anyone can learn. It is
the thinking behind a navigation app, a hospital schedule, and a video game. It 
rests on four pillars.

## The four pillars

  |  Pillar |  What it means |  Everyday example |  
   |  **Decomposition** |  Breaking a big problem into smaller, easier parts |  Planning a party: pick a date, make a guest list, plan food, arrange music |  
 |  **Pattern recognition** |  Noticing what is similar or repeats |  Seeing that making any sandwich involves choosing bread, a filling, and a way to put them together |  
 |  **Abstraction** |  Focusing on what matters and ignoring unneeded details |  A subway map shows stops and lines, not every street |  
 |  **Algorithm** |  Writing clear, ordered steps that solve the problem |  A recipe, or directions to your house |

## Try it: making a sandwich

 1. **Decompose:** get ingredients, prepare the bread, add the filling, put it together,
    clean up.
 2. **Find patterns:** a peanut butter sandwich and a turkey sandwich follow the same
    steps with different ingredients.
 3. **Abstract:** the color of the plate does not matter, but the type of bread and
    filling do.
 4. **Write the algorithm:** exact steps, such as take two slices of bread from the
    bag and place them on the plate, open the jar, and so on.

## Try it: buying a plane ticket

You could break it into choosing a destination, picking dates, comparing prices,
entering traveler information, and paying. Many travel sites follow the same steps,
which is a pattern. The site can hide the details of how airlines set prices, which
is abstraction, while the booking steps themselves form an algorithm.

## Why it matters

These skills help in every subject and job. They also form the base of programming,
where you must tell a computer what to do one precise step at a time.

## Check your understanding

 1. Break down the problem “prepare for the first day at a new job” into at least four
    smaller tasks.
 2. Give an example of a pattern you notice in two different games.
 3. What details would you ignore, and what would you keep, in a map that shows how
    to walk from the cafeteria to the gym?

Use this lesson’s Key Terms page to build your glossary.