Convert "String" sqrt(#) into numerical value
I found the use of Sqrt[...] to be cumbersome, why have the case in that format, and why have the [] style braces?

I would normally not recommend this, but a simple solution, if you trust, or can sanitize your inputs, is to just use the eval function.

for $_ ( @rootList ){
    $_ =~ s/Sqrt\[(.+)\]/sqrt($1)/;
    $_ = eval($_);
    $@ and die $@;
}


That does it..... all of it. Convert Sqrt[...] to sqrt(...), and eval the result.