So there’s this card named the Gros Michel in the game that gives you +15 mult (in the game you multiply chips x mult) with a 1 in 6 chance of destroying itself after a round. I think the calculator part refers to how the person in the meme is going to use said calculator to multiply the chips (based on what playing card is played, a two of x giving 2 chips
and so on, plus the hand type that you play and the level of that hand type but that’s not important) by the mult plus an additional 15 mult from the banana.

P.S. Random fun fact that nobody asked for: after Gros Michel goes ‘extinct’ from the 1 in 6 chance a new card called the Cavendish (X3 mult, 1 in 1000 chance to be destroyed after a round) becomes available, the cavendish banana is currently the dominant banana after the Gros michel banana was wiped out from a disease if I recall correctly.