A computer will follow coded instructions nearly instantly-and with no mistakes! If an error occurs, the fault is with the code, or software, and not the computer circuitry. In this activity, students will model the instructions, variables, and calculations of a computer program, 1 line of code after another. The skills they practice will be useful for writing programs of their own, as well as debugging their programs. The activity also demonstrates the remarkable speed and accuracy at which computers complete tasks.