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Last updated on August 27, 2025
311 in binary is written as 100110111 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 311 in the binary system.
The process of converting 311 from decimal to binary involves dividing the number 311 by 2. Here, it is getting 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 311 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 311 by 2 until getting 0 as the quotient is 100110111. 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 311.
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 100110111 in binary is indeed 311 in the decimal number system.
311 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 311 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 less than 311, we stop at 28 = 256.
Step 2 - Identify the largest power of 2: In the previous step, we stopped at 28 = 256. 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, 311. Since 28 is the number we are looking for, write 1 in the 28 place. Now the value of 28, which is 256, is subtracted from 311. 311 - 256 = 55.
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, 55. So, the next largest power of 2 is 25, which is less than or equal to 55. Now, we have to write 1 in the 25 place. And then subtract 32 from 55. 55 - 32 = 23.
Step 4 - 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, 23. So, the next largest power of 2 is 24, which is less than or equal to 23. Now, we have to write 1 in the 24 place. And then subtract 16 from 23. 23 - 16 = 7.
Step 5 - 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, 7. So, the next largest power of 2 is 22, which is less than or equal to 7. Now, we have to write 1 in the 22 place. And then subtract 4 from 7. 7 - 4 = 3.
Step 6 - 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, 3. So, the next largest power of 2 is 21, which is less than or equal to 3. Now, we have to write 1 in the 21 place. And then subtract 2 from 3. 3 - 2 = 1.
Step 7 - 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, 1. So, the next largest power of 2 is 20, which is less than or equal to 1. Now, we have to write 1 in the 20 place. And then subtract 1 from 1. 1 - 1 = 0. We need to stop the process here since the remainder is 0.
Step 8 - Identify the unused place values: In steps 2 to 7, we wrote 1 in the 28, 25, 24, 22, 21, and 20 places. Now, we can just write 0s in the remaining places, which are 27, 26, and 23. Now, by substituting the values, we get, 1 in the 28 place 0 in the 27 place 0 in the 26 place 1 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 Therefore, 100110111 is 311 in binary.
Grouping Method: In this method, we divide the number 311 by 2. Let us see the step-by-step conversion.
Step 1 - Divide the given number 311 by 2. 311 / 2 = 155. Here, 155 is the quotient and 1 is the remainder.
Step 2 - Divide the previous quotient (155) by 2. 155 / 2 = 77. Here, the quotient is 77 and the remainder is 1.
Step 3 - Repeat the previous step. 77 / 2 = 38. Now, the quotient is 38, and 1 is the remainder.
Step 4 - Repeat the previous step. 38 / 2 = 19. Here, the remainder is 0.
Step 5 - Repeat the previous step. 19 / 2 = 9. Here, the remainder is 1.
Step 6 - Repeat the previous step. 9 / 2 = 4. Here, the remainder is 1.
Step 7 - Repeat the previous step. 4 / 2 = 2. Here, the remainder is 0.
Step 8 - Repeat the previous step. 2 / 2 = 1. Here, the remainder is 0.
Step 9 - Repeat the previous step. 1 / 2 = 0. Here, the remainder is 1. And we stop the division here because the quotient is 0.
Step 10 - Write down the remainders from bottom to top. Therefore, 311 (decimal) = 100110111 (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 311. Since the answer is 28, write 1 next to this power of 2. Subtract the value (256) from 311. So, 311 - 256 = 55. Find the largest power of 2 less than or equal to 55. The answer is 25. So, write 1 next to this power. Now, 55 - 32 = 23. Find the largest power of 2 less than or equal to 23. The answer is 24. So, write 1 next to this power. Now, 23 - 16 = 7. Find the largest power of 2 less than or equal to 7. The answer is 22. So, write 1 next to this power. Now, 7 - 4 = 3. Find the largest power of 2 less than or equal to 3. The answer is 21. So, write 1 next to this power. Now, 3 - 2 = 1. Find the largest power of 2 less than or equal to 1. The answer is 20. So, write 1 next to this power. Now, 1 - 1 = 0. Since there is no remainder, we can write 0 next to the remaining powers (27, 26, and 23). Final conversion will be 100110111.
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, 311 is divided by 2 to get 155 as the quotient and 1 as the remainder. Now, 155 is divided by 2. Here, we will get 77 as the quotient and 1 as the remainder. Dividing 77 by 2, we get 1 as the remainder and 38 as the quotient. Divide 38 by 2 to get 0 as the remainder and 19 as the quotient. Divide 19 by 2 to get 1 as the remainder and 9 as the quotient. Divide 9 by 2 to get 1 as the remainder and 4 as the quotient. Divide 4 by 2 to get 0 as the remainder and 2 as the quotient. Divide 2 by 2 to get 0 as the remainder and 1 as the quotient. Divide 1 by 2 to get 1 as the remainder and 0 as the quotient. We stop the division once the quotient becomes 0. Now, we write the remainders upside down to get the binary equivalent of 311, 100110111.
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., 28, 27, 26, 25, 24, 23, 22, 21, and 20. Find the largest power that fits into 311. 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 311, we use 0s for 27, 26, and 23 and 1s for 28, 25, 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 311.
Memorize to speed up conversions: We can memorize the binary forms for numbers 1 to 311. 1 → 1, 2 → 10, 3 → 11, 4 → 100, 5 → 101, 6 → 110, 7 → 111, 8 → 1000, 9 → 1001, 10 → 1010, ..., 311 → 100110111.
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 e.g., 16 is even and its binary form is 10000. Here, the binary of 16 ends in 0. If the number is odd, then its binary equivalent will end in 1. For e.g., the binary of 311 (an odd number) is 100110111. 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 311 from decimal to binary using the place value method.
100110111
28 is the largest power of 2, which is less than or equal to 311.
So place 1 next to 28.
Subtracting 256 from 311, we get 55.
So the next largest power would be 25.
So place another 1 next to 25.
Now, subtracting 32 from 55, we get 23.
Continue this process, placing 1s next to 24, 22, 21, and 20 while subtracting their values from the remainder.
Now, we just place 0s in the remaining powers of 2, which are 27, 26, and 23.
By using this method, we can find the binary form of 311.
Convert 311 from decimal to binary using the division by 2 method.
100110111
Divide 311 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 311 to binary using the representation method.
100110111
Break the number 311 into powers of 2 and find the largest powers of 2.
We get 2^8. So 1 is placed next to 28.
Next, 311 - 256 = 55.
Now, the largest power of 2 is 25.
Once again, 1 is placed next to 25.
Continue this process, subtracting the largest power of 2 from the remainder and placing 1s next to these powers until the remainder is 0.
Fill in with zeros for unused powers of 2.
By following this method, we get the binary value of 311 as 100110111.
How is 311 written in decimal, octal, and binary form?
Decimal form - 311 Octal - 467 Binary - 100110111
The decimal system is also called the base 10 system.
In this system, 311 is written as 311 only.
We have already seen how 311 is written as 100110111 in binary.
So, let us focus on the octal system, which is base 8.
To convert 311 to octal, we need to divide 311 by 8.
So 311 / 8 = 38 with 7 as the remainder.
In the next step, divide the quotient from the previous step (38) by 8.
So 38 / 8 = 4 with 6 as the remainder.
Finally, divide 4 by 8 to get 0 with 4 as the remainder.
The division process stops here because the quotient is now 0.
Here, the remainders 4, 6, and 7 have to be written in reverse order.
So, 467 is the octal equivalent of 311.
Express 311 - 100 in binary.
1101011
311 - 100 = 211 So, we need to write 211 in binary.
Start by dividing 211 by 2.
We get 105 as the quotient and 1 as the remainder.
Next, divide 105 by 2.
Now we get 52 as the quotient and 1 as the remainder.
Continue this process until the quotient is 0.
Now write the remainders from bottom to top to get 1101011 (binary of 211).
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.