The first time you encounter a news headline declaring *”Stocks Surge 12% in a Single Quarter”* or read about *”Inflation Hitting 8.5% Year-over-Year”*, your brain instinctively registers the magnitude—but do you truly grasp *how* that number was derived? Percent change isn’t just a cold calculation; it’s the invisible thread stitching together economic forecasts, scientific breakthroughs, […]