What is 999999999999999999999999999999999999999999999999999999999999999999999999999999999 squared =???

I counted 59  "9s"

So......this number can be written  as  10^59  - 1  

To see why.....notice that 99  = 10^2 - 1     ...the 10 is raised to the number of "9s" in 99....!!!

So, we have

(10^59 - 1)^2  =

(10^59 - 1) (10^59 - 1)   =

10^108 - 2*10^59  + 1

I'm not sure that this "simplifies" things much, though  !!!

10.00000000E+29 but this answer is only for the first 15 number 9's, my tablets calculator will not go any higher.