Slide Rules: Slide rules are historical mechanical analog calculators used for mathematical calculations, including multiplication, division, logarithms, and trigonometric functions. They consist of two rule-like scales—one fixed and one movable—that slide alongside each other. Slide rules were widely used by engineers, scientists, and students for calculations before the advent of electronic calculators and computers. Their simplicity and portability made them valuable tools for performing complex calculations in a variety of fields. Although slide rules have largely been replaced by digital calculators, they remain historically significant and continue to be appreciated for their educational and nostalgic value.