can someone explain the meaning from this signed binary number?

Question

1000(-1) = 15
1(-1)000=8

Answer 1

Well, this looks strange. Could you give some more context? Seems to be a short form of
10000
-00001
------------
...
etc
So 1*2^4 + 0*2^3 + ... + (-1)*2^0 = 16-1 = 15
1*2^4 + (-1)*2^3 + 0*2^2 + ... + 0*2^0 = 16-8 = 8

Answer 2

thanks for answering 😁... actually the question only tell that this is signed binary number and the example is
1000(-1)=2^4-2^0=15 and
1(-1)000=2^4-2^3=8
but maybe your explanation is right😁... i will try make the code from you example...😁😁