Last updated on August 19th, 2025
202 in binary is written as 11001010 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 202 binary system.
The process of converting 202 from decimal to binary involves dividing the number 202 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 202 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 202 by 2 until getting 0 as the quotient is 11001010. 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 202. 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 11001010 in binary is indeed 202 in the decimal number system.
202 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 202 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. 2^0 = 1 2^1 = 2 2^2 = 4 2^3 = 8 2^4 = 16 2^5 = 32 2^6 = 64 2^7 = 128 2^8 = 256 Since 256 is greater than 202, we stop at 2^7 = 128.
Step 2 - Identify the largest power of 2: In the previous step, we stopped at 2^7 = 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, 202. Since 2^7 is the number we are looking for, write 1 in the 2^7 place. Now the value of 2^7, which is 128, is subtracted from 202. 202 - 128 = 74.
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, 74. So, the next largest power of 2 is 2^6 = 64. Now, we have to write 1 in the 2^6 places. And then subtract 64 from 74. 74 - 64 = 10.
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, 10. So, the next largest power of 2 is 2^3 = 8. Now, we have to write 1 in the 2^3 places. And then subtract 8 from 10. 10 - 8 = 2.
Step 5 - Identify the next largest power of 2: In this step, we find that 2^1 = 2 fits exactly into the result from the previous step. We write 1 in the 2^1 places and subtract 2 from 2. 2 - 2 = 0. We need to stop the process here since the remainder is 0.
Step 6 - Identify the unused place values: In steps 2, 3, 4, and 5, we wrote 1 in the 2^7, 2^6, 2^3, and 2^1 places. Now, we can just write 0s in the remaining places, which are 2^5, 2^4, 2^2, and 2^0. Now, by substituting the values, we get: 0 in the 2^0 place 1 in the 2^1 place 0 in the 2^2 place 1 in the 2^3 place 0 in the 2^4 place 0 in the 2^5 place 1 in the 2^6 place 1 in the 2^7 place
Step 7 - Write the values in reverse order: We now write the numbers upside down to represent 202 in binary. Therefore, 11001010 is 202 in binary.
Grouping Method: In this method, we divide the number 202 by 2. Let us see the step-by-step conversion.
Step 1 - Divide the given number 202 by 2. 202 / 2 = 101. Here, 101 is the quotient and 0 is the remainder.
Step 2 - Divide the previous quotient (101) by 2. 101 / 2 = 50. Here, the quotient is 50 and the remainder is 1.
Step 3 - Repeat the previous step. 50 / 2 = 25. Now, the quotient is 25, and 0 is the remainder.
Step 4 - Repeat the previous step. 25 / 2 = 12. Here, the quotient is 12, and the remainder is 1.
Step 5 - Repeat the previous step. 12 / 2 = 6. Here, the quotient is 6, and the remainder is 0.
Step 6 - Repeat the previous step. 6 / 2 = 3. Here, the quotient is 3, and the remainder is 0.
Step 7 - Repeat the previous step. 3 / 2 = 1. Here, the quotient is 1, and 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, 202 (decimal) = 11001010 (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 202. Since the answer is 2^7, write 1 next to this power of 2. Subtract the value (128) from 202. So, 202 - 128 = 74. Find the largest power of 2 less than or equal to 74. The answer is 2^6. So, write 1 next to this power. Now, 74 - 64 = 10. Continue this process until 0 is obtained. Final conversion will be 11001010.
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, 202 is divided by 2 to get 101 as the quotient and 0 as the remainder. Now, 101 is divided by 2. Here, we will get 50 as the quotient and 1 as the remainder. Dividing 50 by 2, we get 25 as the quotient and 0 as the remainder. Continue this process until the quotient becomes 0. Now, we write the remainders upside down to get the binary equivalent of 202, 11001010.
This rule also involves breaking the number into powers of 2. Identify the powers of 2 and write it down in decreasing order, i.e., 2^7, 2^6, 2^5, 2^4, 2^3, 2^2, 2^1, and 2^0. Find the largest power that fits into 202. 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 202, we use 1s for 2^7, 2^6, 2^3, 2^1, and 0s for 2^5, 2^4, 2^2, and 2^0.
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 202.
Memorize to speed up conversions: We can memorize the binary forms for numbers 1 to 202. 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, 202 is even, and its binary form is 11001010. Here, the binary of 202 ends in 0. If the number is odd, then its binary equivalent will end in 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 202 from decimal to binary using the place value method.
11001010
2^7 is the largest power of 2, which is less than or equal to 202. So place 1 next to 2^7. Subtracting 128 from 202, we get 74. So the next largest power would be 2^6. So place another 1 next to 2^6. Now, subtracting 64 from 74, we get 10. Then place 1 next to 2^3, and subtract 8 from 10 to get 2. Place another 1 next to 2^1 and subtract 2 from 2 to get 0. Now, we just place 0s in the remaining powers of 2, which are 2^5, 2^4, 2^2, and 2^0. By using this method, we can find the binary form of 202.
Convert 202 from decimal to binary using the division by 2 method.
11001010
Divide 202 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 202 to binary using the representation method.
11001010
Break the number 202 into powers of 2 and find the largest powers of 2. We get 2^7. So 1 is placed next to 2^7. Next, 202 - 128 = 74. Now, the largest power of 2 is 2^6. Once again, 1 is placed next to 2^6. Next, 74 - 64 = 10, place 1 next to 2^3, subtract 8 to get 2, place 1 next to 2^1, and subtract 2 to get 0. After getting 0, fill in with zeros for unused powers of 2. By following this method, we get the binary value of 202 as 11001010.
How is 202 written in decimal, octal, and binary form?
Decimal form - 202 Octal - 312 Binary - 11001010
The decimal system is also called the base 10 system. In this system, 202 is written as 202 only. We have already seen how 202 is written as 11001010 in binary. So, let us focus on the octal system, which is base 8. To convert 202 to octal, we need to divide 202 by 8. So 202 / 8 = 25 with 2 as the remainder. In the next step, divide the quotient from the previous step (25) by 8. So 25 / 8 = 3 with 1 as the remainder. Finally, divide 3 by 8 to get 0 with a remainder of 3. The division process stops here because the quotient is now 0. Here, 3, 1, and 2 are the remainders, and they have to be written in reverse order. So, 312 is the octal equivalent of 202.
Express 202 - 50 in binary.
10010010
202 - 50 = 152 So, we need to write 152 in binary. Start by dividing 152 by 2. We get 76 as the quotient and 0 as the remainder. Next, divide 76 by 2. Now we get 38 as the quotient and 0 as the remainder. Divide 38 by 2 to get 19 as the quotient and 0 as the remainder. Divide 19 by 2 to get 9 as the quotient and 1 as the remainder. Divide 9 by 2 to get 4 as the quotient and 1 as the remainder. Divide 4 by 2 to get 2 as the quotient and 0 as the remainder. Divide 2 by 2 to get 1 as the quotient and 0 as the remainder. 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 10010010 (binary of 152).
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.
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