Convert decimal +61 and +27 to binary using the signed 2’s complement representation and enough digits to accommodate the numbers. Then perform the binary equivalent of (27) + (-61), (-27) + (+61), and (-27) + (-61). Convert then answers back to decimal and verify that they are correct.

  the sum is 01011000₂ = 88

Step-by-step explanation:

For numbers of magnitude less than 128, it is convenient to use an 8-bit representation. I find it works will to convert back and forth through the octal (base-8) representation, as each base-8 digit converts nicely to three (3) base-2 bits.

  61 = 8·7 +5 = 075₈ = 00 111 101₂

  27 = 8·3 +3 = 033₈ = 00 011 011₂

Then ...

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Starting from the right, we can convert the binary back to octal, then to decimal by considering 3 bits at a time:

  01 011 000₂ = 130₈ = 1·8² +3·8 +0 = 64 +24 = 88

The binary sum is the same as the decimal sum.

step-by-step explanation: