In 1949, economist Bill Phillips created MONIAC, a hydraulic analogue computer model of the British economy. He found that by tuning the machine, its accuracy could be adjusted to within 2% of the real economy. A total of fourteen MONIACs were built for various customers.
The MONIAC was the inspration for the Glooper in Terry Pratchett’s Making Money, which could actually influence the economy of the Discworld city of Ankh-Morpork, a capability MONIAC lacked.
Pratchett’s Glooper, in turn, inspired the GLOOPER rule in Fourmilab’s Cellular Automata Laboratory, which allows modelling complex fluid flow.
I think a better example of dividing by zero in a national economy might have been artificially holding interest rates near zero while engaging in an unprecedented bender of deficit spending and money printing.