I need help writing a formula or macro that can automatically trim numbers in an area of cells, ex A3 to A55, my knowledge about Excel is unfortunately not big enough so I hope some will help 
The numbers come from a barcode scanner, they look like these examples:
30xx2200755, 30xx + 2200755 and 2201755, xx is entered as these numbers vary, it is 30xx and 30xx + that's needs to be removed.
It would be best with a formula to monitor the cells, but a macro that can do it with a single press can also be used
Hope there are some one who will help

The numbers come from a barcode scanner, they look like these examples:
30xx2200755, 30xx + 2200755 and 2201755, xx is entered as these numbers vary, it is 30xx and 30xx + that's needs to be removed.
It would be best with a formula to monitor the cells, but a macro that can do it with a single press can also be used

Hope there are some one who will help
