# Electronics - Arithmetic Operations and Circuits - Discussion

Discussion Forum : Arithmetic Operations and Circuits - General Questions (Q.No. 11)

11.

Binary subtraction of a decimal 15 from 43 will utilize which two's complement?

Discussion:

10 comments Page 1 of 1.
Mrudhula said:
1 decade ago

43's two's complement is 010001.

15's two's complement is 0001.

Binary subtraction is 010000 may I know what is wrong in my answer.

15's two's complement is 0001.

Binary subtraction is 010000 may I know what is wrong in my answer.

Nikhil said:
1 decade ago

43 is 101011 --- (1).

15 is 1111 ----- (2).

Subtract (1)-(2)=110000.

And 2's comp of 110000 is 110001.

15 is 1111 ----- (2).

Subtract (1)-(2)=110000.

And 2's comp of 110000 is 110001.

Sourav said:
9 years ago

I don't agree with your answer @Nikhil, 2's comp can be made up after 1's compliment but you did it in a wrong way to make the answer correct.

Brajendra Kumar Mishra said:
9 years ago

I think answer will be (C).

43 = 1 0 1 0 1 1.

15 = 0 0 1 1 1 1.

Take the 2's complement of 15 =1 1 0 0 0 1.

Then add this value with binary equivalent of 43.

Will get,

1 0 1 0 1 1

+1 1 0 0 0 1

=1 0 1 1 1 0 0.

Then discard the carry output you will get 011100 so option will be (C).

We can verify it by taking simply 43 - 15 = 28.

When you will convert option C in decimal number that will give the correct answer that is '28'.

So option C is the correct answer.

43 = 1 0 1 0 1 1.

15 = 0 0 1 1 1 1.

Take the 2's complement of 15 =1 1 0 0 0 1.

Then add this value with binary equivalent of 43.

Will get,

1 0 1 0 1 1

+1 1 0 0 0 1

=1 0 1 1 1 0 0.

Then discard the carry output you will get 011100 so option will be (C).

We can verify it by taking simply 43 - 15 = 28.

When you will convert option C in decimal number that will give the correct answer that is '28'.

So option C is the correct answer.

Rathi said:
9 years ago

@Brajendra.

Your way of subtraction is correct. But in the Question "will utilize which two's complement".

I think they ask value of the 2's complement which is used in that subtraction. So 2's complement of 15 = 1 1 0 0 0 1.

So D is Correct Answer.

Your way of subtraction is correct. But in the Question "will utilize which two's complement".

I think they ask value of the 2's complement which is used in that subtraction. So 2's complement of 15 = 1 1 0 0 0 1.

So D is Correct Answer.

Chethan said:
9 years ago

Yea @Rathi, you are right, Thanks for the meaning of the question.

Jaskaran singh(jass) said:
6 years ago

Please explain, what is mean of two's complement?

SPS said:
6 years ago

@Jaskaran.

Two's complement is nothing but the complement of given no plus 1.

Two's complement is nothing but the complement of given no plus 1.

Nisha said:
6 years ago

The question is that which 2's complement utilize.

And it is 15. It is subtracted and we make two's complement of it which is 110001.

And it is 15. It is subtracted and we make two's complement of it which is 110001.

Yamuna said:
3 years ago

Still, I didn't understand. Please, can you explain once?

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