A number is decreased by \( 12 \% \) to give 528 . Find the number. A number is decreased by \( 55 \% \) to give 540 . Find the number.

To find the original number when it is decreased by 12% to equal 528, you can set up the equation: \( x - 0.12x = 528 \) or \( 0.88x = 528 \). Solving for \( x \) gives you \( x = \frac{528}{0.88} = 600 \). For the second part, when a number is decreased by 55% to give 540, you can use a similar equation: \( y - 0.55y = 540 \) or \( 0.45y = 540 \). Solving for \( y \) gives you \( y = \frac{540}{0.45} = 1200 \). So, the numbers are \( 600 \) and \( 1200 \). Have you ever wondered why percentages are such a popular way to express changes? Historically, the concept of percentages dates back to ancient civilizations, where they were used for trade and taxation. The ease of using a percentage to represent a portion of a whole has kept it in style across the ages! In practical terms, understanding how to work with percentages is extremely valuable! For example, if you're negotiating a discount on your next shopping spree or calculating your grades in school, knowing how to quickly find original amounts from given percentages can save you both time and money!