How to represent a small change in a larger number

[MCPO John-117]

Hey Everyone,

So I was doing some homework and one of my solutions was

500.0000000000139x10^-9 m

It wanted us to find the wavelength of doppler shifted light at a low speed and so the change is very small from the initial wavelength of 500x10^-9 m

I was wondering if there would be an easier way or some proper notation to write this small increase as a single number.

I could easily write 500nm+1.39x10^-11nm (5x10^-7m+1.39x10^-20m) but it doesn't feel right to have a plus sign in an answer. is there a notation that would help here?

is the notation compoundable?
how would you write
1000000000000000000000000000001.00000000000000000001
in a compact form other than
1x10^30+1+1x10^-20 ?

Thanks

 

[Number Nine]

You could represent only the value of the change (e.g. "a total change of +139x10^something")