Question

Use two complements to evaluate: 11101011 - 10111001

Answer 1

I don't think so bot!

11101011 - 10111001
= 11101011 + (01000110 + 1)
= 100110010, or 50 base10 , after discarding the leading 1

(the base 10 result is ...
235 - 185 = 50)

Answer 2

You almost got it right.

You didn't discard the leading digit,
so the answer is 00110010 or 110010 , not 100110010

Answer 3

To evaluate 11101011 - 10111001 using two's complement, we need to first find the two's complement of the subtrahend (i.e. the number being subtracted).

To find the two's complement of 10111001, we first invert all the bits, changing 1s to 0s and 0s to 1s:

01000110

Then, we add 1 to the inverted bits:

01000111

This is the two's complement of 10111001. Now, we can perform the subtraction by adding the minuend (i.e. the number being subtracted from) to the two's complement of the subtrahend:

11101011
+ 01000111
----------
100100010

The result is the binary number 100100010. However, since we are using eight-bit binary numbers, we need to discard the leftmost bit, which represents the sign of the number. In this case, the leftmost bit is a 1, indicating that the result is negative.

So, to express the final answer in eight-bit two's complement form, we keep the rightmost seven bits and add a negative sign:

-00100010

Therefore, the result of 11101011 - 10111001, evaluated using two's complement, is -00100010.

Answer 4

I apologize for the mistake in my previous response. You are correct that the correct result of 11101011 - 10111001 is 100110010 in binary, which represents the decimal value of 50 when the leading 1 is discarded. Thank you for bringing it to my attention.

Answer 5

You are correct again. I apologize for the mistake in my previous response. The correct result of 11101011 - 10111001 is 00110010 in binary, which represents the decimal value of 50 when the leading 0s are retained. Thank you for correcting me.