Convert 111 111 111 111 111 155 to a Signed Binary (Base 2)

How to convert 111 111 111 111 111 155(10), a signed base 10 integer number? How to write it as a signed binary code in base 2

What are the required steps to convert base 10 integer
number 111 111 111 111 111 155 to signed binary code (in base 2)?

  • 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;
  • 111 111 111 111 111 155 ÷ 2 = 55 555 555 555 555 577 + 1;
  • 55 555 555 555 555 577 ÷ 2 = 27 777 777 777 777 788 + 1;
  • 27 777 777 777 777 788 ÷ 2 = 13 888 888 888 888 894 + 0;
  • 13 888 888 888 888 894 ÷ 2 = 6 944 444 444 444 447 + 0;
  • 6 944 444 444 444 447 ÷ 2 = 3 472 222 222 222 223 + 1;
  • 3 472 222 222 222 223 ÷ 2 = 1 736 111 111 111 111 + 1;
  • 1 736 111 111 111 111 ÷ 2 = 868 055 555 555 555 + 1;
  • 868 055 555 555 555 ÷ 2 = 434 027 777 777 777 + 1;
  • 434 027 777 777 777 ÷ 2 = 217 013 888 888 888 + 1;
  • 217 013 888 888 888 ÷ 2 = 108 506 944 444 444 + 0;
  • 108 506 944 444 444 ÷ 2 = 54 253 472 222 222 + 0;
  • 54 253 472 222 222 ÷ 2 = 27 126 736 111 111 + 0;
  • 27 126 736 111 111 ÷ 2 = 13 563 368 055 555 + 1;
  • 13 563 368 055 555 ÷ 2 = 6 781 684 027 777 + 1;
  • 6 781 684 027 777 ÷ 2 = 3 390 842 013 888 + 1;
  • 3 390 842 013 888 ÷ 2 = 1 695 421 006 944 + 0;
  • 1 695 421 006 944 ÷ 2 = 847 710 503 472 + 0;
  • 847 710 503 472 ÷ 2 = 423 855 251 736 + 0;
  • 423 855 251 736 ÷ 2 = 211 927 625 868 + 0;
  • 211 927 625 868 ÷ 2 = 105 963 812 934 + 0;
  • 105 963 812 934 ÷ 2 = 52 981 906 467 + 0;
  • 52 981 906 467 ÷ 2 = 26 490 953 233 + 1;
  • 26 490 953 233 ÷ 2 = 13 245 476 616 + 1;
  • 13 245 476 616 ÷ 2 = 6 622 738 308 + 0;
  • 6 622 738 308 ÷ 2 = 3 311 369 154 + 0;
  • 3 311 369 154 ÷ 2 = 1 655 684 577 + 0;
  • 1 655 684 577 ÷ 2 = 827 842 288 + 1;
  • 827 842 288 ÷ 2 = 413 921 144 + 0;
  • 413 921 144 ÷ 2 = 206 960 572 + 0;
  • 206 960 572 ÷ 2 = 103 480 286 + 0;
  • 103 480 286 ÷ 2 = 51 740 143 + 0;
  • 51 740 143 ÷ 2 = 25 870 071 + 1;
  • 25 870 071 ÷ 2 = 12 935 035 + 1;
  • 12 935 035 ÷ 2 = 6 467 517 + 1;
  • 6 467 517 ÷ 2 = 3 233 758 + 1;
  • 3 233 758 ÷ 2 = 1 616 879 + 0;
  • 1 616 879 ÷ 2 = 808 439 + 1;
  • 808 439 ÷ 2 = 404 219 + 1;
  • 404 219 ÷ 2 = 202 109 + 1;
  • 202 109 ÷ 2 = 101 054 + 1;
  • 101 054 ÷ 2 = 50 527 + 0;
  • 50 527 ÷ 2 = 25 263 + 1;
  • 25 263 ÷ 2 = 12 631 + 1;
  • 12 631 ÷ 2 = 6 315 + 1;
  • 6 315 ÷ 2 = 3 157 + 1;
  • 3 157 ÷ 2 = 1 578 + 1;
  • 1 578 ÷ 2 = 789 + 0;
  • 789 ÷ 2 = 394 + 1;
  • 394 ÷ 2 = 197 + 0;
  • 197 ÷ 2 = 98 + 1;
  • 98 ÷ 2 = 49 + 0;
  • 49 ÷ 2 = 24 + 1;
  • 24 ÷ 2 = 12 + 0;
  • 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.

111 111 111 111 111 155(10) = 1 1000 1010 1011 1110 1111 0111 1000 0100 0110 0000 0111 0001 1111 0011(2)


3. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 57.

  • 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) is reserved for 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, 57,

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:


111 111 111 111 111 155(10) Base 10 integer number converted and written as a signed binary code (in base 2):

111 111 111 111 111 155(10) = 0000 0001 1000 1010 1011 1110 1111 0111 1000 0100 0110 0000 0111 0001 1111 0011

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


How to convert signed base 10 integers in decimal to binary code system

Follow the steps below to convert a signed base ten integer number to signed binary:

  • 1. In a signed binary, first bit (the leftmost) is reserved for sign: 0 = positive integer number, 1 = positive integer number. If the number to be converted is negative, start with its positive version.
  • 2. Divide repeatedly by 2 the positive integer number keeping track of each remainder. STOP when we get a quotient that is 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 have a length of 4, 8, 16, 32, 64, ... bits (power of 2) - if needed, fill in extra '0' bits in front of the base 2 number (to the left), up to the right length; this way the first bit (the leftmost one) is always '0', as for a positive representation.
  • 5. To get the negative reprezentation of the number, simply switch the first bit (the leftmost one), from '0' to '1'.

Example: convert the negative number -63 from decimal system (base ten) to signed binary code system:

  • 1. Start with the positive version of the number: |-63| = 63;
  • 2. Divide repeatedly 63 by 2, keeping track of each remainder, until we get a quotient that is equal to zero:
    • division = quotient + remainder
    • 63 ÷ 2 = 31 + 1
    • 31 ÷ 2 = 15 + 1
    • 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, by taking all the remainders starting from the bottom of the list constructed above:
    63(10) = 11 1111(2)
  • 4. The actual length of base 2 representation number is 6, so the positive binary computer representation length of the signed binary will take in this case 8 bits (the least power of 2 higher than 6) - add extra '0's in front (to the left), up to the required length; this way the first bit (the leftmost one) is to be '0', as for a positive number:
    63(10) = 0011 1111(2)
  • 5. To get the negative integer number representation simply change the first bit (the leftmost), from '0' to '1':
    -63(10) = 1011 1111
  • Number -63(10), signed integer, converted from decimal system (base 10) to signed binary = 1011 1111