[Math] truncation in two’s complment

binarycomputer-arithmetic

My textbook gives an example of truncating a signed number in two's complement from 4 bits to 3 bits. It truncates -4 to 4. I am little confused by this, because the binary representation of -4 is 1100. 1100 being truncated to 3 bits at the most significant side yields 100, which is -4 in decimal.

I am not sure, if I am missing something, but according to the book it should be 4. Am I missing something?

Best Answer

You are correct, either they truncated from a signed number to an unsigned number or they forgot a minus sign.