The range of 1’s complement form is from (-2(n-1)-1) to (2(n-1)-1). i.e., Range of 6 bit 1’s complement form binary number is from -(25-1) to (25-1) which is minimum -31 (i.e., 100000) to maximum value +31 (i.e., 011111). And zero (0) has two representation, -0 (i.e., 1 11111) and +0 (i.e., 0 00000).