For example, in the first one, x +y shud be .20000051 x 10^1 (An extra zero)
Same with the second one
x+y = …2 x 10 + .51 x 10^-2 = 2 + . 0051 = 2.0051 = .20051 x 10^1 => .200 in 2 decimal places.
You are right.
I have updated the notes.
For the first, it does not matter very much, as saturation is the target, but I have changed the 10^{-5} to 10^{-4}.
For the second, third and fourth, as the marginal cases are the target, I have changed the 10^{-2} to 10^{-1}.
With these changes to the negative exponents, the results are correct.
Thanks for pointing out!