One that I know: labs.<p>Having a calculator next to your precision balance or your micrometer is always useful. Many times, you always need to do the same operation with the quantity you are measuring, so it is worth to even program the calculator for it, if you have the possibility.<p>In this situation, the phone is usually hidden by a lab coat and you are wearing a pair of gloves . Moreover, the computer is out of reach or you do not want to touch. The calculator gets the job done much faster and you do not have to worry so much when it is soaked in acid.