Calculator (Apple)

Apple's Calculator is a faithful digital pocket calculator, and that fidelity is both its clarity and its ceiling. The buttons are big, evenly gridded, and labeled exactly like the physical object they imitate, so anyone can use it without instruction. A view toggle swaps the basic keypad for scientific and programmer modes, a tidy progressive-disclosure trick that keeps the default uncluttered. But the immediate-execution model means the running result is the only memory you get; there is no editable expression line, so a mistyped digit forces a restart, and you cannot see the chain of operations that produced the number on screen. A paper-tape view records past entries but stays out of the way. It optimizes for the casual sum and punishes anyone composing a longer calculation.