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DEMO: Binary to Decimal

Binary-to-decimal conversion is a foundational networking skill required for certifications such as the CCNA. This topic covers the positional value method for converting binary numbers to their decimal equivalents.

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About this video

Binary-to-decimal conversion is a foundational skill for anyone working in networking or pursuing certifications such as the CCNA. Every IP address, subnet mask, and network calculation at the professional level relies on the ability to move accurately between binary and decimal representations, making this one of the most frequently applied concepts in the field. The conversion process uses a positional value table in which each bit position corresponds to a specific power of two, starting at 1 on the right and doubling with each position moving left: 1, 2, 4, 8, 16, 32, 64, and 128. To convert a binary number to decimal, identify which positions contain a 1 and add their corresponding values. The binary number 1011, for instance, has 1s in the 8, 2, and 1 positions, producing a decimal value of 11. Similarly, a number with 1s in the 32, 8, and 2 positions yields 42. Building proficiency with this method requires deliberate practice until the conversions become automatic. Starting with the positional value table as a reference is a practical approach, and over time most practitioners internalize the values well enough to work without it. Accurate and efficient binary-to-decimal conversion is a prerequisite for the more advanced addressing and subnetting topics covered throughout networking and cybersecurity training.

What you'll learn

What's covered

Binary to Decimal Conversion

Aligned to

CompTIA Tech+
1.1 Compare and contrast notational systems.
1.2 Compare and contrast fundamental data types and their characteristics.

Key terms

Binary
The base-2 number system that uses only the digits 0 and 1; the native language of digital computers, which store and process data as electrical on/off states.
Decimal
The base-10 number system using digits 0–9; the standard system used in everyday counting and arithmetic, and the most common format for presenting numeric output to humans.
Positional Notation
A numbering system where the value of a digit is determined by both the digit itself and its position within the number.
Binary Value Table
A reference table listing the powers of 2 assigned to each bit position, used to convert binary numbers to decimal.

Transcript

We're going to learn how to convert from binary to decimal. This is key to the rest of the course. Make sure you understand the contents of what we're talking about; we will be using it a lot. Make sure you're proficient in it. If you are going after your certification tests, like a CCNA certification test, then you will probably need to know how to do this. Make sure you understand this.

Using the Table

We're going to use our table to figure these out. It's going to make things a lot easier to use this table. With time, you can get rid of the table and won't need it, but I do recommend at least starting out with the table.

So what we're going to do is put in some numbers in here. I'm going to do a 1 0 1 1, and we're going to convert that. It's pretty easy to do. All we have to do is take 8, because we have one of those, plus a 2, so we're going to add a 2, plus a 1 since we have one of those. Add this together: so 8, 9, 10, 11. So the answer for this is 11. That's the decimal equivalent to this binary number.

Let's do another one here. Maybe we have a 32 and how about an 8 and a 2. And there we have it. We just take 32, plus we have an 8, plus we have a 2, so this is going to be 42. So 42, one of my favorite numbers there. It's the meaning of life, the universe, and everything. So there we have it. That's how to convert these numbers.

Practice Worksheet

What I have here is a worksheet that you can go through and add up the numbers here, figure out what your answers are for each one of these, and then we will come back and check this. So go through these. If you've done that, here's the answer, so check this against your answer and see how well you did.

Excellent. Once again, this is going to be pretty key to making sure you're successful through the rest of the course. So make sure you understand this, practice this, make sure you've got it down and can do it accurately.

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