# Two's Complement: Integer -> Binary: 805 306 427 Convert the Integer Number to a Signed Binary in Two's Complement Representation. Write the Base Ten Decimal System Number as a Binary Code (Written in Base Two)

## Signed integer number 805 306 427(10) converted and written as a signed binary in two's complement representation (base 2) = ?

### 1. Divide the number repeatedly by 2:

#### We stop when we get a quotient that is equal to zero.

• division = quotient + remainder;
• 805 306 427 ÷ 2 = 402 653 213 + 1;
• 402 653 213 ÷ 2 = 201 326 606 + 1;
• 201 326 606 ÷ 2 = 100 663 303 + 0;
• 100 663 303 ÷ 2 = 50 331 651 + 1;
• 50 331 651 ÷ 2 = 25 165 825 + 1;
• 25 165 825 ÷ 2 = 12 582 912 + 1;
• 12 582 912 ÷ 2 = 6 291 456 + 0;
• 6 291 456 ÷ 2 = 3 145 728 + 0;
• 3 145 728 ÷ 2 = 1 572 864 + 0;
• 1 572 864 ÷ 2 = 786 432 + 0;
• 786 432 ÷ 2 = 393 216 + 0;
• 393 216 ÷ 2 = 196 608 + 0;
• 196 608 ÷ 2 = 98 304 + 0;
• 98 304 ÷ 2 = 49 152 + 0;
• 49 152 ÷ 2 = 24 576 + 0;
• 24 576 ÷ 2 = 12 288 + 0;
• 12 288 ÷ 2 = 6 144 + 0;
• 6 144 ÷ 2 = 3 072 + 0;
• 3 072 ÷ 2 = 1 536 + 0;
• 1 536 ÷ 2 = 768 + 0;
• 768 ÷ 2 = 384 + 0;
• 384 ÷ 2 = 192 + 0;
• 192 ÷ 2 = 96 + 0;
• 96 ÷ 2 = 48 + 0;
• 48 ÷ 2 = 24 + 0;
• 24 ÷ 2 = 12 + 0;
• 12 ÷ 2 = 6 + 0;
• 6 ÷ 2 = 3 + 0;
• 3 ÷ 2 = 1 + 1;
• 1 ÷ 2 = 0 + 1;

## How to convert signed integers from decimal system to signed binary in two's complement representation

### Follow the steps below to convert a signed base 10 integer number to signed binary in two'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, keeping track of each remainder, until 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 must have 4, 8, 16, 32, 64, ... bit length (a power of 2) - if needed, add extra bits on 0 in front (to the left) of the base 2 number above, up to the required length, so that the first bit (the leftmost) will 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 1s and all 1 bits with 0s (reversing the digits).
• 6. To get the negative integer number, in signed binary two's complement representation, add 1 to the number above.

### Example: convert the negative number -60 from the decimal system (base ten) to signed binary in two's complement:

• 1. Start with the positive version of the number: |-60| = 60
• 2. Divide repeatedly 60 by 2, keeping track of each remainder:
• division = quotient + remainder
• 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, by taking all the remainders starting from the bottom of the list constructed above:
60(10) = 11 1100(2)
• 4. Bit length of base 2 representation number is 6, so the positive binary computer representation of a signed binary will take in this particular case 8 bits (the least power of 2 larger than 6) - add extra 0 digits in front of the base 2 number, up to the required length:
60(10) = 0011 1100(2)
• 5. To get the negative integer number representation in signed binary one's complement, replace all the 0 bits with 1s and all 1 bits with 0s (reversing the digits):
!(0011 1100) = 1100 0011
• 6. To get the negative integer number, signed binary in two's complement representation, add 1 to the number above:
-60(10) = 1100 0011 + 1 = 1100 0100