David, unless you have long hair (and you might!) use your wife's hair dryer on high setting and heat the numbers one at a time until the glue will let go with a small pull on that number. Or you can use a steam iron, not directly on the metal but on an old moistened terry towel or wash cloth until the generated steam heat loosens the number. Take your time, and it helps greatly if the sun is shining warmly on the space you are working on, even before you start--like at noon so both front and rear are being warmed simultaneously.

You will almost surely have a ghost of the old number, and since your numbers are the same this will give you a guide for replacing each of them.

Good luck. It always helps.

Donald