Birthday Card

My sister emailed me to ask for Laura's new address to mail her a birthday card.  I looked it up in my address book and sent her the address that I had written down.  Then later Barb and I were going to send her a birthday card and I had written Laura's new address on a little piece of paper and given it to Barb when Laura sent it to me.  I didn't realize that she had also sent her new address to Barb separately.  Rather than looking up Laura's address on her phone Barb was going to use the address on the little piece of paper that was sitting on her side table.  Then she realized that I can be dyslexic with numbers.  So she looked up the number that Laura had sent her and indeed I had reversed the numbers on the apartment number.  I had written 310 instead of 301 on the note and in my address book.  So Barb decided to email my sister to tell her about the mistake just in case she hadn't mailed the card yet.  But the address that Barb had typed in her phone had the wrong postal code.  Barb had written an N where there should have been a M.  I had had the right postal code but the wrong apartment number.  Now my sister had the right apartment number but the wrong postal code.  It didn't matter because my sister had already sent the card.  Barb just had to change the postal code she had written on the envelope from an N to an M and then send the card.