Basic Calculator

A calculator performs arithmetic: addition, subtraction, multiplication, and division. Understanding operator precedence prevents common errors. Order of operations (PEMDAS/BODMAS): Parentheses first, then Exponents, then Multiplication and Division (left to right), then Addition and Subtraction (left to right). Without this, complex expressions produce unexpected results. Common mistake: 2 + 3 × 4. The correct answer is 14 (multiply first), not 20 (left to right). A basic calculator processes left to right; a scientific calculator respects PEMDAS. Percentage key: The % key divides by 100. '50%' = 0.5. '200 × 15%' = 30. To find a price after 20% discount: multiply by 80% (or 0.8). Memory functions: M+ adds to memory, MR recalls it, MC clears it. Useful for running totals when summing multiple values without writing them down.