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MathNet 2026 — Part 10 Question 40

Math Olympiad Vault · MathNet 2026 — Part 10

Question 40

A Mystic Four Calculator has a four-digit display and four buttons. The calculator works as follows: Pressing button 1 replaces the number in the display with $1$; Pressing button 2 divides the number in the display by $2$; Pressing button 3 subtracts $3$ from the number in the display; Pressing button 4 multiplies the number in the display by $4$.

Initially the display shows $0$. Any operation yielding a negative, fractional, or five-digit answer is ignored.


a. Can $2007$ appear in the display?


b. Can $2008$ appear in the display?