Convert Decimal 111 100 101 172 to Signed Binary in One's (1's) Complement Representation

How to convert decimal number 111 100 101 172(10) to a signed binary in one's (1's) complement representation

What are the steps to convert decimal number
111 100 101 172 to a signed binary in one's (1's) complement representation?

  • A signed integer, written in base ten, or a decimal system number, is a number written using the digits 0 through 9 and the sign, which can be positive (+) or negative (-). If positive, the sign is usually not written. A number written in base two, or binary, is a number written using only the digits 0 and 1.

1. Divide the number repeatedly by 2:

Keep track of each remainder.

Stop when you get a quotient that is equal to zero.


  • division = quotient + remainder;
  • 111 100 101 172 ÷ 2 = 55 550 050 586 + 0;
  • 55 550 050 586 ÷ 2 = 27 775 025 293 + 0;
  • 27 775 025 293 ÷ 2 = 13 887 512 646 + 1;
  • 13 887 512 646 ÷ 2 = 6 943 756 323 + 0;
  • 6 943 756 323 ÷ 2 = 3 471 878 161 + 1;
  • 3 471 878 161 ÷ 2 = 1 735 939 080 + 1;
  • 1 735 939 080 ÷ 2 = 867 969 540 + 0;
  • 867 969 540 ÷ 2 = 433 984 770 + 0;
  • 433 984 770 ÷ 2 = 216 992 385 + 0;
  • 216 992 385 ÷ 2 = 108 496 192 + 1;
  • 108 496 192 ÷ 2 = 54 248 096 + 0;
  • 54 248 096 ÷ 2 = 27 124 048 + 0;
  • 27 124 048 ÷ 2 = 13 562 024 + 0;
  • 13 562 024 ÷ 2 = 6 781 012 + 0;
  • 6 781 012 ÷ 2 = 3 390 506 + 0;
  • 3 390 506 ÷ 2 = 1 695 253 + 0;
  • 1 695 253 ÷ 2 = 847 626 + 1;
  • 847 626 ÷ 2 = 423 813 + 0;
  • 423 813 ÷ 2 = 211 906 + 1;
  • 211 906 ÷ 2 = 105 953 + 0;
  • 105 953 ÷ 2 = 52 976 + 1;
  • 52 976 ÷ 2 = 26 488 + 0;
  • 26 488 ÷ 2 = 13 244 + 0;
  • 13 244 ÷ 2 = 6 622 + 0;
  • 6 622 ÷ 2 = 3 311 + 0;
  • 3 311 ÷ 2 = 1 655 + 1;
  • 1 655 ÷ 2 = 827 + 1;
  • 827 ÷ 2 = 413 + 1;
  • 413 ÷ 2 = 206 + 1;
  • 206 ÷ 2 = 103 + 0;
  • 103 ÷ 2 = 51 + 1;
  • 51 ÷ 2 = 25 + 1;
  • 25 ÷ 2 = 12 + 1;
  • 12 ÷ 2 = 6 + 0;
  • 6 ÷ 2 = 3 + 0;
  • 3 ÷ 2 = 1 + 1;
  • 1 ÷ 2 = 0 + 1;

2. Construct the base 2 representation of the positive number:

Take all the remainders starting from the bottom of the list constructed above.

111 100 101 172(10) = 1 1001 1101 1110 0001 0101 0000 0010 0011 0100(2)

3. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 37.

  • A signed binary's bit length must be equal to a power of 2, as of:
  • 21 = 2; 22 = 4; 23 = 8; 24 = 16; 25 = 32; 26 = 64; ...
  • The first bit (the leftmost) indicates the sign:
  • 0 = positive integer number, 1 = negative integer number

The least number that is:


1) a power of 2

2) and is larger than the actual length, 37,

3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)


=== is: 64.


4. Get the positive binary computer representation on 64 bits (8 Bytes):

If needed, add extra 0s in front (to the left) of the base 2 number, up to the required length, 64.


Decimal Number 111 100 101 172(10) converted to signed binary in one's complement representation:

111 100 101 172(10) = 0000 0000 0000 0000 0000 0000 0001 1001 1101 1110 0001 0101 0000 0010 0011 0100

Spaces were used to group digits: for binary, by 4, for decimal, by 3.


How to convert signed integers from the decimal system to signed binary in one's complement representation

Follow the steps below to convert a signed base 10 integer number to signed binary in one's complement representation:

  • 1. If the number to be converted is negative, start with the positive version of the number.
  • 2. Divide repeatedly by 2 the positive representation of the integer number that is to be converted to binary, keeping track of each remainder, until we get a quotient that is equal to ZERO.
  • 3. Construct the base 2 representation of the positive number, by taking all the remainders starting from the bottom of the list constructed above. Thus, the last remainder of the divisions becomes the first symbol (the leftmost) of the base two number, while the first remainder becomes the last symbol (the rightmost).
  • 4. Binary numbers represented in computer language must have 4, 8, 16, 32, 64, ... bit length (a power of 2) - if needed, fill in '0' bits in front (to the left) of the base 2 number calculated above, up to the right length; this way the first bit (leftmost) will always be '0', correctly representing a positive number.
  • 5. To get the negative integer number representation in signed binary one's complement, replace all '0' bits with '1's and all '1' bits with '0's.

Example: convert the negative number -49 from the decimal system (base ten) to signed binary one's complement:

  • 1. Start with the positive version of the number: |-49| = 49
  • 2. Divide repeatedly 49 by 2, keeping track of each remainder:
    • division = quotient + remainder
    • 49 ÷ 2 = 24 + 1
    • 24 ÷ 2 = 12 + 0
    • 12 ÷ 2 = 6 + 0
    • 6 ÷ 2 = 3 + 0
    • 3 ÷ 2 = 1 + 1
    • 1 ÷ 2 = 0 + 1
  • 3. Construct the base 2 representation of the positive number, by taking all the remainders starting from the bottom of the list constructed above:
    49(10) = 11 0001(2)
  • 4. The actual bit length of base 2 representation is 6, so the positive binary computer representation of a signed binary will take in this case 8 bits (the least power of 2 that is larger than 6) - add '0's in front of the base 2 number, up to the required length:
    49(10) = 0011 0001(2)
  • 5. To get the negative integer number representation in signed binary one's complement, replace all '0' bits with '1's and all '1' bits with '0's:
    -49(10) = 1100 1110
  • Number -49(10), signed integer, converted from the decimal system (base 10) to signed binary in one's complement representation = 1100 1110