Answer: Sometimes abbreviated as LSB, the least significant bit is the lowest bit in a series of numbers in binary. It is either the leftmost or rightmost bit in a binary number, depending on the computer's architecture. If the LSB is on the right, the architecture is called "little-endian." If the LSB is on the left, the architecture is called "big-endian." For example, in a little-endian architecture, the LSB of binary number 00000001 is 1.
I'm not sure which numbers you are referring to, but 3 has the same absolute value as -3, and 7 has the same absolute value as -7, just for an example.