Convert -65 101 111 089 to a Signed Binary in One's (1's) Complement Representation

How to convert decimal number -65 101 111 089(10) to a signed binary in one's (1's) complement representation

What are the steps to convert decimal number
-65 101 111 089 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. Start with the positive version of the number:

|-65 101 111 089| = 65 101 111 089

2. 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;
  • 65 101 111 089 ÷ 2 = 32 550 555 544 + 1;
  • 32 550 555 544 ÷ 2 = 16 275 277 772 + 0;
  • 16 275 277 772 ÷ 2 = 8 137 638 886 + 0;
  • 8 137 638 886 ÷ 2 = 4 068 819 443 + 0;
  • 4 068 819 443 ÷ 2 = 2 034 409 721 + 1;
  • 2 034 409 721 ÷ 2 = 1 017 204 860 + 1;
  • 1 017 204 860 ÷ 2 = 508 602 430 + 0;
  • 508 602 430 ÷ 2 = 254 301 215 + 0;
  • 254 301 215 ÷ 2 = 127 150 607 + 1;
  • 127 150 607 ÷ 2 = 63 575 303 + 1;
  • 63 575 303 ÷ 2 = 31 787 651 + 1;
  • 31 787 651 ÷ 2 = 15 893 825 + 1;
  • 15 893 825 ÷ 2 = 7 946 912 + 1;
  • 7 946 912 ÷ 2 = 3 973 456 + 0;
  • 3 973 456 ÷ 2 = 1 986 728 + 0;
  • 1 986 728 ÷ 2 = 993 364 + 0;
  • 993 364 ÷ 2 = 496 682 + 0;
  • 496 682 ÷ 2 = 248 341 + 0;
  • 248 341 ÷ 2 = 124 170 + 1;
  • 124 170 ÷ 2 = 62 085 + 0;
  • 62 085 ÷ 2 = 31 042 + 1;
  • 31 042 ÷ 2 = 15 521 + 0;
  • 15 521 ÷ 2 = 7 760 + 1;
  • 7 760 ÷ 2 = 3 880 + 0;
  • 3 880 ÷ 2 = 1 940 + 0;
  • 1 940 ÷ 2 = 970 + 0;
  • 970 ÷ 2 = 485 + 0;
  • 485 ÷ 2 = 242 + 1;
  • 242 ÷ 2 = 121 + 0;
  • 121 ÷ 2 = 60 + 1;
  • 60 ÷ 2 = 30 + 0;
  • 30 ÷ 2 = 15 + 0;
  • 15 ÷ 2 = 7 + 1;
  • 7 ÷ 2 = 3 + 1;
  • 3 ÷ 2 = 1 + 1;
  • 1 ÷ 2 = 0 + 1;

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

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

65 101 111 089(10) = 1111 0010 1000 0101 0100 0001 1111 0011 0001(2)

4. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 36.

  • 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, 36,

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


=== is: 64.


5. 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.


65 101 111 089(10) = 0000 0000 0000 0000 0000 0000 0000 1111 0010 1000 0101 0100 0001 1111 0011 0001

6. Get the negative integer number representation:

  • To write the negative integer number on 64 bits (8 Bytes), as a signed binary in one's complement representation,
  • ... Reverse all the bits from 0 to 1 and from 1 to 0 (flip the digits).


-65 101 111 089(10) = !(0000 0000 0000 0000 0000 0000 0000 1111 0010 1000 0101 0100 0001 1111 0011 0001)


Decimal Number -65 101 111 089(10) converted to signed binary in one's complement representation:

-65 101 111 089(10) = 1111 1111 1111 1111 1111 1111 1111 0000 1101 0111 1010 1011 1110 0000 1100 1110

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