In this lesson, you will learn that computers can only understand whether electricity is on or off. Using these two states to represent the numbers 0 and 1, people build complex electrical circuits that are able to represent sequences of 0s and 1s.

Using binary, you can represent decimal numbers as binary sequences of 0s and 1s, and therefore are able to represent numbers inside a computer. Once you are able to represent numbers, you are able to represent more complex things. You will see examples of colors and user permissions in this lesson.

You will also learn that this system can be used with other bases, such as octal and hexadecimal. Hexadecimal is important because it allows you to represent long sequences of bits in a more compact a human-readable way.

Knowing binary and different numbering systems, as well as how to work in different systems using Python, is crucial for any data engineer to know.

As you work with each concept in this lesson, you’ll get to apply what you’ve learned from within your browser; there's no need to use your own machine to do the exercises. The Python environment inside of this course includes answer-checking to ensure you've fully mastered each concept before learning the next.

#### Objectives

#### Lesson Outline

1. The Bit

2. The Decimal Number System

3. The Binary Number System

4. Bits and the Binary Number System

5. Other Number Bases

6. Special Cases

7. Hexadecimal

8. Octal

9. Next Steps

10. Takeaways