Continuing the calculator stories.
When I resumed my education, I took some required math courses. Each course had different rules regarding calculators. In the classroom you could use any calculator you wanted. Many students just used their phones and laptops.
Testing time was another story entirely. You had to stand in a line outside the testing center with your ID, pencils and erasers, your scratch paper, your testing book, and your sanctioned calculator without the cover. You were not allowed to get out any other materials once you went to your designated seat.
During the final exam for the semester, my calculator's battery suddenly died and one of the most excellent testing staff was able to lend me one. After that, I always carried two calculators.