(Strip Number 3681, Original Publication Date, 25 May 1981)
Panel 1: We see Elly, Anne and the children attending the party gathered around a table. As Mike tries to grab a stray balloon, Elly starts off the intro for the cake by saying "Okay!" and singing "Happy birthdayyy..."
Panel 2: As she puts down the cake, she smiles and continues singing "to youuu! Happy Birthdayyy to youuuu! Happy Birthday, Dear Lizzie, Happy Birthday to yooooouuuu!!"
Panel 3: As she and Annie start clearing away the dishes, Elly asks her "Who looks a year older? The kid or me?"
Summary: What we have here is the punchline Elly delivers whenever she throws a kid's birthday party; what she means is that she never realized doing more work than she really had to would take so much out of her.