Not to be confused with the PC-4 Calculator that is used by Egon in the scenes "Get Her!" and Terminated.
After a deal was struck at Manhattan City Bank, Egon ran some calculations on his Casio Micro-Mini Calculator. Peter Venkman promised Ray Stantz he was never going to regret it. Ray stated his parents left him that house and he was born there. Peter reassured him he was not going to lose the house and everybody had three mortgages nowadays. Ray questioned settling at 19 percent and not bargaining. Egon finished a calculation and flashed it to Ray. Egon stated the interest rate alone for the first five years came to $95,000.
- The exact model is a Casio Micro-Mini M-810.
- On cover B of Ghostbusters Year One Issue #4, next to the Post It is Egon's Casio Micro-Mini Calculator from Chapter 4: Terminated.
- 1984, the year of the first movie, is on the screen of the Micro-Mini Calculator.