Ancient Times: Early Counting Tools

• Abacus (ca. 2400 BCE): Used in ancient civilizations like Mesopotamia and China for basic arithmetic operations.

17th Century: Mechanical Innovations

• Slide Rule (1622): Developed by William Oughtred for multiplication and division using logarithmic scales.
• Pascal's Calculator (1642): Blaise Pascal's invention for addition and subtraction using gears.
• Leibniz's Stepped Reckoner (1673): A mechanical calculator by Gottfried Wilhelm Leibniz for multiplication and division.

19th Century: Industrial Revolution

• Difference Engine (1822): Charles Babbage's design for solving polynomial equations.
• Arithmometer (1851): The first commercially successful mechanical calculator.

20th Century: Electronic Revolution

• First Electronic Calculator (1961): ANITA Mk VII used vacuum tubes for calculations.
• Pocket Calculators (1970s): Portable calculators from Casio, HP, and Texas Instruments.

Modern Era: Digital and Advanced Calculators

• Scientific Calculators (1970s-1980s): Advanced calculators for trigonometry and logarithms.
• Graphing Calculators (1985): Devices like the TI-81 for visualizing equations.
• Smartphone Apps (2000s-present): Advanced calculator apps integrated into smartphones.