I taught middle school math and was required to use the calculators in class. I had a classroom set of calculators for the students to use, and it was my responsibility to make sure the calculators were not stolen and that the batteries were not taken out of them.
Biggest.Waste.Of.Time, and the calculators were of no value teaching students the concepts my students needed to learn.
And in case you find yourself in the position of being required to keep track of the calculators and batteries that you have handed over to middle school students who are looking for ways to defeat you, I positioned myself in front of the door, and I had the “calculator box” on my person. Students were required to file out one-by-one and have the calculator on when they handed it to me so that I could confirm the batteries were in the calculator where they belonged.