Question 6
A calculator has 15 buttons: the digits 0–9, the four operations (+, −, ×, ÷), and “=”. It currently displays 2021. What is the least number of button presses needed to obtain 1?
Entry convention for grading: continue from the displayed 2021 without clearing or replacing it. Enter each binary operation followed by an explicit nonnegative whole-number operand, and finish with “=”. No implicit/repeated operands or calculator-specific shortcuts are allowed.
Entry convention for grading: continue from the displayed 2021 without clearing or replacing it. Enter each binary operation followed by an explicit nonnegative whole-number operand, and finish with “=”. No implicit/repeated operands or calculator-specific shortcuts are allowed.