If you are only allowed to press the 1 and 0 keys on a calculator with any of the add, take, times, divide and equals keys, what is the fewest number of presses needed to make the number 9 on the calculator?
Enter 38 on a calculator. Now reduce it to 1 by using any operation key and the number 3 only. What is the fewest number of key presses needed (please explain the complete process)?