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101 LearnersLast updated on December 11, 2025

10011001 is a binary number comprised of the digits 0 and 1. The binary system is fundamental in computing and digital electronics. In this topic, we will explore the binary number 10011001 and its significance.
The binary number 10011001 is a sequence of 1s and 0s.
Each position in this number represents a power of 2, starting from the rightmost digit, which represents 20.
Converting this binary number to decimal involves multiplying each digit by its corresponding power of 2 and summing the results.
This is a standard method for understanding binary numbers.
The conversion of 10011001 from binary to decimal involves calculating the value of each bit.
The table below shows the binary digits, their place values as powers of 2, and the calculation that converts this binary number into decimal form:
1 × 27 = 128
0 × 26 = 0
0 × 25 = 0
1 × 24 = 16
1 × 23 = 8
0 × 22 = 0
0 × 21 = 0
1 × 20 = 1
Adding these values: 128 + 16 + 8 + 1 = 153. Therefore, 10011001 in binary is 153 in decimal.
To write a number as 10011001 in binary, you must understand how each digit affects the overall value. Here we explain using different methods how binary numbers are constructed and interpreted.
Expansion Method: Let's break down 10011001 using the expansion method.
Step 1 - Determine the place values: In binary, each position is a power of 2. Identify the powers for each position in the number.
20 = 1
21 = 2
22 = 4
23 = 8
24 = 16
25 = 32
26 = 64
27 = 128
Step 2 - Assign the powers to the binary digits: The binary number 10011001 has digits in the 27, 24, 23, and 20 positions. These positions have the binary digit '1', so they contribute to the value.
Step 3 - Calculate the decimal equivalent: Multiply each binary digit by its corresponding power of 2 and add the results. This yields 153 as the decimal equivalent of 10011001.


Several rules guide the conversion of binary numbers:
Rule 1: Place Value Method Identify the largest power of 2 that fits into the number, then proceed with smaller powers, filling in 0s where the binary digit is absent.
Rule 2: Binary Addition When adding binary numbers, remember: 0+0=0, 1+0=1, 1+1=10 (carry the 1).
Rule 3: Understanding Bit Significance The leftmost bit is the most significant, while the rightmost bit is the least significant. This determines their influence on the total value.
Rule 4: Limitation of Binary Binary uses only 0s and 1s, making it ideal for digital systems that rely on two-state (on/off) logic.
Here are some useful tips for working with binary numbers:
Memorize common binary values: Knowing binary equivalents for small decimal numbers can speed up conversion.
Recognize patterns: Binary follows predictable patterns, such as each digit doubling in value from right to left.
Odd and even rule: Even binary numbers end in 0, odd numbers end in 1.
Practice with tables: Creating tables of binary and decimal equivalents can aid memory.
Cross-verify answers: Convert binary results back to decimal to check accuracy.
When converting binary numbers, several common mistakes can occur.
Here are tips to avoid them.
Convert 153 from decimal to binary using the expansion method.
10011001
The binary representation of 153 involves finding which powers of 2 sum to 153.
The largest power less than or equal to 153 is 27.
The process continues with 24, 23, and 20, resulting in 10011001.
Convert 153 from decimal to binary using the division by 2 method.
10011001
Divide 153 by 2 repeatedly, keeping track of remainders.
Write down the remainders from bottom to top to get the binary result.
Express 153 in binary using the representation method.
10011001
Identify powers of 2 that sum to 153, placing 1s in these positions and 0s elsewhere.
The pattern of 1s and 0s forms the binary number 10011001.
How is 153 written in decimal, octal, and binary form?
Decimal form - 153
Octal - 231
Binary - 10011001
Decimal 153 is written as 231 in octal, achieved by converting the decimal to base 8.
In binary, it is represented as 10011001, using base 2 conversion.
Express 153 - 75 in binary.
1001100
Subtract 75 from 153 to get 78.
Then, convert 78 to binary using division by 2, resulting in the binary number 1001100.

Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
: She loves to read number jokes and games.






