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Computer Science Basics•August 18, 2026•5 min read
Demystifying Binary: How Computers Count Using Only 1s and 0s
AUTHOR: elv1labs Academy // elv1labs
DEMYSTIFYING BINARY: HOW COMPUTERS COUNT USING ONLY 1S AND 0S
Humans count using ten digits (0 through 9). This is the decimal system, also called Base-10. Computers, however, operate using only two digits: 0 and 1. This is the binary system, or Base-2.
The hardware inside a computer relies on electronic switches. Measuring two distinct states—ON (current flows) and OFF (no current)—is far more reliable than trying to measure ten different levels of electrical current. Consequently, computers communicate using binary.
HOW BASE-2 COUNTING WORKS
In the decimal system, each column represents a power of 10:
Ones (10^0), Tens (10^1), Hundreds (10^2), and so on.
The number 143 represents: (1 * 100) + (4 * 10) + (3 * 1).
In binary, each column represents a power of 2:
Ones (2^0 = 1), Twos (2^1 = 2), Fours (2^2 = 4), Eights (2^3 = 8), Sixteens (2^4 = 16), and so on.
Let's convert the binary number 1011 into decimal:
Column positions and values:
- Eights column (8): 1
- Fours column (4): 0
- Twos column (2): 1
- Ones column (1): 1
Calculation:
Add the values of the columns containing a 1:
(1 * 8) + (0 * 4) + (1 * 2) + (1 * 1) = 8 + 0 + 2 + 1 = 11.
Thus, the binary string 1011 is equal to the decimal number 11.
Let's convert another binary number, 11001:
- Sixteens column (16): 1
- Eights column (8): 1
- Fours column (4): 0
- Twos column (2): 0
- Ones column (1): 1
Calculation:
16 + 8 + 0 + 0 + 1 = 25.
The binary string 11001 is equal to the decimal number 25.
BITS AND BYTES
Bit: A single binary digit (0 or 1). This is the smallest unit of digital storage.
Byte: A group of 8 bits. A single byte can store a decimal value from 0 to 255.
Computers represent text characters by assigning each character a specific number. In the standard ASCII coding system, the capital letter 'A' is mapped to the number 65. In memory, this is stored as the byte 01000001. By combining millions of bytes, computers represent complex media like high-definition photos, audio, and program code.
Reference: E. Balagurusamy, "Fundamentals of Computers", Chapter 3: Memory and Storage Systems.
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