The document discusses how to use a calculator effectively by following the proper order of operations. It explains that calculators may give different answers depending on the order terms are entered due to differences in how calculators evaluate expressions. The proper order of operations is BODMAS: Brackets, Orders (Exponents), Division, Multiplication, Addition, Subtraction. Examples are provided to illustrate the importance of the order of operations and using brackets to evaluate multi-step calculations correctly on a calculator.