IS It Possible To input A did range in the dial plan routing table for example 230-260 strip and add change 270-299"
Absolutely! You'll need to match the ranges though... the first is a range of 31 digits, and the second is a range of 30 digits..
In any case, you'll need 3 dial plan routing entries:
Set the "pattern to match" on the first one to 23; set the "delete digits" to 2; set "add digits" to 27; that will take care of 230 to 239; do the same for 24, and 25, adding 28 and 29 respectively... piece of cake, dude!