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Last updated on August 12, 2025
215 in binary is written as 11010111 because the binary system uses only two digits, 0 and 1, to represent numbers. This number system is widely used in computer systems. In this topic, we are going to learn about the binary representation of 215.
The process of converting 215 from decimal to binary involves dividing the number 215 by 2. 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 215 to binary. In the last step, the remainder is noted down bottom side up, and that becomes the converted value.
For example, the remainders noted down after dividing 215 by 2 until getting 0 as the quotient is 11010111. 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 11010111.
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 11010111 in binary is indeed 215 in the decimal number system.
215 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 215 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 215, 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 in this step, we have to identify the largest power of 2, which is less than or equal to the given number, 215. 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 215. 215 - 128 = 87.
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, 87. So, the next largest power of 2 is 26, which is less than or equal to 87. Now, we have to write 1 in the 26 places. And then subtract 64 from 87. 87 - 64 = 23.
Step 4 - Repeat the process for the remaining value: Continue finding the largest suitable power of 2 for the remainder 23, which is 24 = 16. Write 1 in the 24 place and subtract 16 from 23.
23 - 16 = 7.
For 7, the largest power of 2 is 22 = 4.
Write 1 in the 22 place and subtract 4 from 7.
7 - 4 = 3. Finally, for 3, the largest power of 2 is 21 = 2.
Write 1 in the 21 place and subtract 2 from 3.
3 - 2 = 1.
Finally, 1 is 20.
Step 5 - Identify the unused place values:
In step 2 to 4, we wrote 1 in the 27, 26, 24, 22, 21, and 20 places.
Now, we can just write 0s in the remaining places, which are 25 and 23.
Now, by substituting the values, we get, 1 in the 27 place 1 in the 26 place 0 in the 25 place 1 in the 24 place 0 in the 23 place 1 in the 22 place 1 in the 21 place 1 in the 20 place
Step 6 - Write the values in reverse order: We now write the numbers upside down to represent 215 in binary.
Therefore, 11010111 is 215 in binary.
Grouping Method: In this method, we divide the number 215 by 2. Let us see the step-by-step conversion.
Step 1 - Divide the given number 215 by 2. 215 / 2 = 107. Here, 107 is the quotient and 1 is the remainder.
Step 2 - Divide the previous quotient (107) by 2. 107 / 2 = 53. Here, the quotient is 53 and the remainder is 1.
Step 3 - Repeat the previous step. 53 / 2 = 26. Now, the quotient is 26, and 1 is the remainder.
Step 4 - Repeat the previous step. 26 / 2 = 13. Here, the remainder is 0.
Step 5 - Repeat the previous step. 13 / 2 = 6. Here, the remainder is 1.
Step 6 - Repeat the previous step. 6 / 2 = 3. Here, the remainder is 0.
Step 7 - Repeat the previous step. 3 / 2 = 1. Here, the remainder is 1.
Step 8 - Repeat the previous step. 1 / 2 = 0. Here, the remainder is 1. And we stop the division here because the quotient is 0.
Step 9 - Write down the remainders from bottom to top.
Therefore, 215 (decimal) = 11010111 (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 215.
Since the answer is 27, write 1 next to this power of 2.
Subtract the value (128) from 215. So, 215 - 128 = 87.
Find the largest power of 2 less than or equal to 87.
The answer is 26.
So, write 1 next to this power. Now, 87 - 64 = 23.
Repeat the process until the remainder is 0.
Final conversion will be 11010111.
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, 215 is divided by 2 to get 107 as the quotient and 1 as the remainder.
Now, 107 is divided by 2. Here, we will get 53 as the quotient and 1 as the remainder.
Dividing 53 by 2, we get 26 as the quotient and 1 as the remainder.
Divide 26 by 2 to get 13 as the quotient and 0 as the remainder.
Divide 13 by 2 to get 6 as the quotient and 1 as the remainder.
Divide 6 by 2 to get 3 as the quotient and 0 as the remainder.
Divide 3 by 2 to get 1 as the quotient and 1 as the remainder.
Divide 1 by 2 to get 0 as the quotient and 1 as the remainder.
We stop the division once the quotient becomes 0. Now, we write the remainders upside down to get the binary equivalent of 215, 11010111.
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 215.
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.
To convert 215, we use 0s for 25 and 23, and 1s for 27, 26, 24, 22, 21, and 20.
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 215.
Memorize to speed up conversions: We can memorize the binary forms for numbers with specific patterns.
Recognize the patterns: There is a peculiar pattern when converting numbers from decimal to binary.
1 → 1
1 + 1 = 2 → 10
2 + 2 = 4 → 100
4 + 4 = 8 → 1000
8 + 8 = 16 → 10000
16 + 16 = 32 → 100000…and so on.
This is also called the double and add rule. Even and odd rule: Whenever a number is even, its binary form will end in 0. For example, 214 is even, and its binary form is 11010110.
If the number is odd, then its binary equivalent will end in 1. For example, the binary of 215 (an odd number) is 11010111. As you can see, the last digit here is 1.
Cross-verify the answers: Once the conversion is done, we can cross-verify the answers by converting the number back to the decimal form. This will eliminate any unforeseen errors in conversion.
Practice by using tables: Writing the decimal numbers and their binary equivalents on a table will help us remember the conversions.
Here, let us take a look at some of the most commonly made mistakes while converting numbers to binary.
Convert 215 from decimal to binary using the place value method.
11010111
27 is the largest power of 2, which is less than or equal to 215.
So place 1 next to 27.
Subtracting 128 from 215, we get 87.
So the next largest power would be 26.
So place another 1 next to 26.
Continuing this method with the remaining powers of 2 and remainders, we place 0s and 1s accordingly and find the binary form of 215.
Convert 215 from decimal to binary using the division by 2 method.
11010111
Divide 215 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 215 to binary using the representation method.
11010111
Break the number 215 into powers of 2 and find the largest powers of 2.
We get 27.
So 1 is placed next to 27.
Continue this process for each remainder by subtracting and placing 1s and 0s in the correct positions until the remainder is 0.
By following this method, we get the binary value of 215 as 11010111.
How is 215 written in decimal, octal, and binary form?
Decimal form - 215 Octal - 327 Binary - 11010111
The decimal system is also called the base 10 system. In this system, 215 is written as 215 only.
We have already seen how 215 is written as 11010111 in binary.
So, let us focus on the octal system, which is base 8.
To convert 215 to octal, we need to divide 215 by 8.
So 215 / 8 = 26 with 7 as the remainder. In the next step, divide the quotient from the previous step (26) by 8.
So 26 / 8 = 3 with 2 as the remainder. Finally, 3 / 8 = 0 with 3 as the remainder.
The division process stops here because the quotient is now 0.
Here, 7, 2, and 3 are the remainders, and they have to be written in reverse order.
So, 327 is the octal equivalent of 215.
Express 215 - 5 in binary.
11010010
215 - 5 = 210 So, we need to write 210 in binary.
Start by dividing 210 by 2. We get 105 as the quotient and 0 as the remainder.
Next, divide 105 by 2.
Now we get 52 as the quotient and 1 as the remainder.
Divide 52 by 2 to get 26 as the quotient and 0 as the remainder.
Divide 26 by 2 to get 13 as the quotient and 0 as the remainder.
Divide 13 by 2 to get 6 as the quotient and 1 as the remainder.
Divide 6 by 2 to get 3 as the quotient and 0 as the remainder.
Divide 3 by 2 to get 1 as the quotient and 1 as the remainder.
Finally, divide 1 by 2 to get 0 as the quotient and 1 as the remainder.
Now write the remainders from bottom to top to get 11010010 (binary of 210).
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.