A calculator is a device or software that performs mathematical operations on numbers. Calculators can vary in complexity, from simple ones that can only perform basic arithmetic, to scientific ones that can handle trigonometry, logarithms, and other advanced functions. Calculators are useful tools for students, professionals, and anyone who needs to perform calculations quickly and accurately. Some calculators are designed for specific purposes, such as financial calculators, graphing calculators, or engineering calculators. Calculators can also be embedded in other devices, such as watches, phones, or computers.