Summarize this article:
Last updated on August 19, 2025
239 in binary is written as 11101111 because the binary system uses only two digits, 0 and 1, to represent numbers. This number system is used widely in computer systems. In this topic, we are going to learn about the binary representation of the number 239.
The process of converting 239 from decimal to binary involves dividing the number 239 by 2. Here, it is divided by 2 because the binary number system uses only 2 digits (0 and 1). The quotient becomes the dividend in the next step, and the process continues until the quotient becomes 0.
This is a commonly used method to convert 239 to binary. In the last step, the remainder is noted down from bottom to top, and that becomes the converted value. For example, the remainders noted down after dividing 239 by 2 until getting 0 as the quotient is 11101111. Remember, the remainders here have been written upside down.
In the table shown below, the first column shows the binary digits (1 and 0) as 11101111. The second column represents the place values of each digit, and the third column is the value calculation, where the binary digits are multiplied by their corresponding place values.
The results of the third column can be added to cross-check if 11101111 in binary is indeed 239 in the decimal number system.
239 can be converted easily from decimal to binary. The methods mentioned below will help us convert the number. Let’s see how it is done.
Expansion Method: Let us see the step-by-step process of converting 239 using the expansion method.
Step 1 - Figure out the place values: In the binary system, each place value is a power of 2. Therefore, in the first step, we will ascertain the powers of 2. 20 = 1 21 = 2 22 = 4 23 = 8 24 = 16 25 = 32 26 = 64 27 = 128 28 = 256 Since 256 is greater than 239, we stop at 27 = 128.
Step 2 - Identify the largest power of 2: In the previous step, we stopped at 27 = 128. This is because we have to identify the largest power of 2, which is less than or equal to the given number, 239. Since 27 is the number we are looking for, write 1 in the 27 place. Now the value of 27, which is 128, is subtracted from 239. 239 - 128 = 111.
Step 3 - Identify the next largest power of 2: In this step, we need to find the largest power of 2 that fits into the result of the previous step, 111. So, the next largest power of 2 is 26 = 64. Write 1 in the 26 place and subtract 64 from 111. 111 - 64 = 47.
Step 4 - Continue the process: Repeat the process of finding the largest power of 2 for the remaining numbers. For 47, the largest power of 2 is 25 = 32. Write 1 in the 25 place. 47 - 32 = 15. For 15, the largest power of 2 is 23 = 8. Write 1 in the 23 place. 15 - 8 = 7. For 7, the largest power of 2 is 22 = 4. Write 1 in the 22 place. 7 - 4 = 3. For 3, the largest power of 2 is 21 = 2. Write 1 in the 21 place. 3 - 2 = 1. For 1, the largest power of 2 is 20 = 1. Write 1 in the 20 place. 1 - 1 = 0.
Step 5 - Write the values in reverse order: We now write the numbers upside down to represent 239 in binary. Therefore, 11101111 is 239 in binary.
Grouping Method: In this method, we divide the number 239 by 2. Let us see the step-by-step conversion.
Step 1 - Divide the given number 239 by 2. 239 / 2 = 119. Here, 119 is the quotient and 1 is the remainder.
Step 2 - Divide the previous quotient (119) by 2. 119 / 2 = 59. Here, the quotient is 59 and the remainder is 1.
Step 3 - Repeat the previous step. 59 / 2 = 29. Now, the quotient is 29 and 1 is the remainder.
Step 4 - Repeat the previous step. 29 / 2 = 14. Here, the quotient is 14 and 1 is the remainder.
Step 5 - Continue the process: 14 / 2 = 7. Quotient is 7, remainder is 0. 7 / 2 = 3. Quotient is 3, remainder is 1. 3 / 2 = 1. Quotient is 1, remainder is 1. 1 / 2 = 0. Quotient is 0, remainder is 1.
Step 6 - Write down the remainders from bottom to top. Therefore, 239 (decimal) = 11101111 (binary).
There are certain rules to follow when converting any number to binary. Some of them are mentioned below:
This is one of the most commonly used rules to convert any number to binary. The place value method is the same as the expansion method, where we need to find the largest power of 2. Let’s see a brief step-by-step explanation to understand the first rule. Find the largest power of 2 less than or equal to 239. Since the answer is 27, write 1 next to this power of 2. Subtract the value (128) from 239. So, 239 - 128 = 111. Find the largest power of 2 less than or equal to 111. The answer is 26. So, write 1 next to this power. Continue the process until you get a remainder of 0.
The division by 2 method is the same as the grouping method. A brief step-by-step explanation is given below for better understanding. First, 239 is divided by 2 to get 119 as the quotient and 1 as the remainder. Now, 119 is divided by 2. Here, we will get 59 as the quotient and 1 as the remainder. Dividing 59 by 2, we get 29 as the quotient and 1 as the remainder. Continue the division process until the quotient becomes 0. Now, we write the remainders upside down to get the binary equivalent of 239, 11101111.
This rule also involves breaking the number into powers of 2. Identify the powers of 2 and write them down in decreasing order i.e., 27, 26, 25, 24, 23, 22, 21, and 20. Find the largest power that fits into 239. Repeat the process and allocate 1s and 0s to the suitable powers of 2. Combine the digits (0 and 1) to get the binary result.
The limitation of the binary system is that only 0s and 1s can be used to represent numbers. The system doesn’t use any other digits other than 0 and 1. This is a base 2 number system, where the binary places represent powers of 2. So, every digit is either a 0 or a 1.
Learning a few tips and tricks is a great way to solve any mathematical problems easily. Let us take a look at some tips and tricks for binary numbers up to 239.
Here, let us take a look at some of the most commonly made mistakes while converting numbers to binary.
Convert 239 from decimal to binary using the place value method.
11101111
27 is the largest power of 2, which is less than or equal to 239.
So place 1 next to 27.
Subtracting 128 from 239, we get 111.
So the next largest power would be 26.
So place another 1 next to 26.
Continue subtracting the largest powers until the remainder is 0.
By using this method, we can find the binary form of 239.
Convert 239 from decimal to binary using the division by 2 method.
11101111
Divide 239 by 2. In the next step, the quotient becomes the new dividend.
Continue the process until the quotient becomes 0.
Now, write the remainders upside down to get the final result.
Convert 239 to binary using the representation method.
11101111
Break the number 239 into powers of 2 and find the largest powers of 2.
We get 27. So 1 is placed next to 27.
Next, 239 - 128 = 111.
Continue to find the largest power of 2 for the remaining number.
By following this method, we get the binary value of 239 as 11101111.
How is 239 written in decimal, octal, and binary form?
Decimal form - 239 Octal - 357 Binary - 11101111
The decimal system is also called the base 10 system. In this system, 239 is written as 239 only.
We have already seen how 239 is written as 11101111 in binary.
So, let us focus on the octal system, which is base 8.
To convert 239 to octal, we need to divide 239 by 8.
So 239 / 8 = 29 with 7 as the remainder
In the next step, divide the quotient from the previous step (29) by 8. So 29 / 8 = 3 with 5 as the remainder.
Finally, divide 3 by 8 to get 0 as the quotient and 3 as the remainder.
Here, 3, 5, and 7 are the remainders, and they have to be written in reverse order. So, 357 is the octal equivalent of 239.
Express 239 - 1 in binary.
11101110
239 - 1 = 238
So, we need to write 238 in binary.
Start by dividing 238 by 2. We get 119 as the quotient and 0 as the remainder.
Next, divide 119 by 2.
Now we get 59 as the quotient and 1 as the remainder.
Continue the division process until the quotient becomes 0.
Now write the remainders from bottom to top to get 11101110 (binary of 238).
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.