Calcolatrici literally translates to "calculators". It's an unexpected word to find in a rap song, making it quite memorable and intriguing.
In the context of the song, Sfera Ebbasta uses it metaphorically to describe himself and his crew as being adept at the "mathematics of the street" – calculating profits from illicit dealings. They are like human calculators, precise and efficient in their street hustle, turning "dirty money" into "clean money" in what he calls "bar lavatrici" (bar washing machines).
The title comes out of one line in Sfera Ebbasta's opening verse: "Matematica di strada, siamo calcolatrici" (Street mathematics, we're calculators). Everything here gets counted. Two paychecks thrown at a stripper, watches bought at list price, a kilo picked up for two in Spain and moved for six back home, dirty money pushed through bars and washing machines: "Soldi sporchi, poi puliti dentro bar lavatrici" (Dirty money, then washed clean inside bars, washing machines). The bragging is arithmetic, and the arithmetic is the whole joke.
The hook drops into Neapolitan and gets blunt about what the money buys you: "Nun te salva 'o Rolex ma te salva 'o Kalash" (A Rolex won't save you but a Kalashnikov will). Geolier's verse is the bleakest stretch, and its worst line is almost tender: "'O pate a 41 incoraggia 'o figlio, 'Bravo, studia'" (The father in 41-bis encourages his son, 'Good boy, study'), a man in maximum-security isolation telling his kid to do his homework. Baby Gang and Simba La Rue finish it at a sprint, plainclothes police on their tail: "Sese, falchi ci stanno inseguendo" (Sese, the plainclothes cops are chasing us). Four rappers, four accents, one calculator.