1101011₂ - 111010₂
1101011
+111010
_______
 110001
_______
= 110001₂

1101010₂ + 101101₂
1101010
+101101
________
10010111
________
= 10010111₂

135₁₀ = 10000111
1's complement  =      0 1 1 1 1 0 0 0
Add 1 bit            =                     +  1
                                    ____________
2's complement  =       0 1 1 1 1 0 01
                                    _____________

=98₁₀ = 110010
8bit format of 98₁₀ =     0 1 1 0 0 0 1 0
1's complement     =     1 0 0 1 1 1 0 1
Add 1 Bit                =                     +1
                                       _____________
2's complement      =    1 0 0 1 1 1 0  1
                                       _____________

98.46₁₀
1. Integer part

2. Fractional part
0.46 x 2 = 0.92 = 0
0.92 x 2 = 1.84 = 1
0.84 x 2 = 1.68 = 1
0.68 x 2 = 1.36 = 1
0.36 x 2 = 0.72 = 0
0.72 x 2 = 1.44 = 1
98.46₁₀ = (1100010.011101...)₂

The method of repeated multiplication by 2 has to be used to convert such kind of decimal fractions.
The steps involved in the method of repeated multiplication by 2:
Step 1: Multiply the decimal fraction by 2 and note. the integer part. The integer part is either 0 or 1.
Step 2: Discard the integer part of the previous product. Multiply the fractional part of the previous product by 2. Repeat Step 1 until the same fraction repeats or terminates (0).
Step 3: The resulting integer part forms a sequence of 0s and 1s that become the binary equivalent of decimal fraction.
Step 4: The final answer is to be written from first. integer part obtained till the last integer part obtained.