I have a spreadsheet that has numbers in the format of:

0001-1234
0258-6847
1658-5487 etc.

Some one has messed up the spreadsheet and now some of the numbers look like:

000112-34
025868-47
165854-87 etc

I need to get the numbers back to their original state. any ideas? some of the things I tried ended up with the number losing the zeros at the beginning.