91Ó°ÊÓ

Percentages are a way to express a number as a fraction of 100. They are widely used in finance, statistics, and everyday calculations to simplify understanding of portions and changes. When you see a "percent," it is denoting parts per hundred.
To understand how percentages work, think of it as a ratio. For instance, if a shirt is labeled with a 20% discount, that's like saying you are reducing the price by 20 parts out of every 100. This makes it easier to visualize reductions and increases.

• If you purchase an item with a 20% discount, you are essentially paying for 80% of the original price.
• Percentages can be added to, subtracted from, or otherwise applied to various numerical values.

Recognizing the practical application of percentages in daily life includes understanding discounts, taxes, interest rates, and more. In our case, the concept of a 20% discount means that the original price is being reduced by 20%.

Decimal conversion is the process of converting a percentage or fraction into a decimal form. This conversion is crucial in performing mathematical operations involving percentages, such as calculations for discounts, taxes, or interests.
For example, converting 20% to a decimal involves dividing the percentage by 100. Thus, the decimal form of 20% is 0.20. This conversion is necessary because decimals are easier to manipulate mathematically than percentages.

• To convert a percentage to a decimal, simply move the decimal point two places to the left.
• Use the converted decimal in calculations to simplify your process.

Using decimals allows us to perform operations like multiplication or division seamlessly. For instance, in discount calculations, the percentage (e.g., 20%) is often converted to a decimal (0.20) for accurate discount amount computations.

Basic arithmetic operations include addition, subtraction, multiplication, and division. They form the foundation of all mathematical calculations and are essential for solving real-life problems like finding discounts, calculating totals, and performing financial transactions.
In our original exercise, the key operation is multiplication. To calculate a discount, you multiply the original price by the decimal representation of the discount percentage.

• To determine the discount amount: Multiply the original price (\(45\)) by the decimal discount rate (\(0.20\)). This gives us \(45 \times 0.20 = 9\).
• The result, 9, is the amount deducted from the original price.

Understanding how to perform these basic arithmetic operations confidently allows for efficient handling of financial decisions and adjustments, such as discount calculations.