(Strip Number 1200, Original Publication Date, 14 September 1987)
Panel 1: Overwhelmed Elly is overwhelmed and asks Thelma how she can play so many cards at once.
Panel 2: Elly tries to follow Thelma when she says that it's a simple matter of scanning the cards and putting the chips (daubers/dabbers hadn't become a thing yet) down with both hands but still manages to look like one of her kids trying to plumb the impenitrable mytsery of percentages.
Panel 3: A man comes along and tells Elly that Thelma can play bingo in her sleep.
Panel 4: Thelma stage-whispers that the last time she won, she knocked the teeth off her nightstand; Elly's expression is one of hopeless confusion.
Summary: We get that Thelma eats, breathes and sleeps bingo. Will Elly? The dumbfounded look on her face suggests that she's probably STILL trying to puzzle out what Mrs B meant by that.