Question 23
Marry writes 1, 2, 3, …, 10 on a board. She repeatedly erases two numbers a, b and replaces them by a−b. What is the fewest number of operations needed for the final result on the board to be 0?
As intended by the source,“final result” means that only one number remains. The alternative reading is discussed in the solution.
As intended by the source,“final result” means that only one number remains. The alternative reading is discussed in the solution.