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When you see a sales tag or promo for a discount, it's important to know how to calculate what you'll save. The process of discount calculation helps you determine the amount you deduct from the original price.

In our example, the cordless phone has an original price of $85. With a 20% discount, this doesn't just mean you pay 80% of the price immediately - you need to calculate the exact amount you'll save first. The formula used is:

\[ \text{Discount Amount} = \text{Original Price} \times \text{Discount Rate (in decimal form)} \]

This helps you find out precisely how much to subtract to get to the discounted price. Understanding this concept ensures you always know the correct price to pay during sales.

Working with percentages is usual in real life, but calculations often require decimals. Decimal conversion is the process of turning percentages into decimals, which is essential for calculations.

To convert a percentage to a decimal, follow these steps:

• Divide the percentage by 100.


• Remove the percent sign.

For example, a 20% discount becomes 0.20 in decimal form. Why? Because \(20\% = 20/100 = 0.20\). Decimal conversion simplifies multiplying and finding proportions when calculating prices and discounts. Being comfortable with this conversion is a powerful tool in everyday math.

Rounding numbers is a crucial skill when dealing with money because currency often deals with two decimal places. This is why we round to the nearest cent or hundredth.

In discount calculations, like in our example, sometimes results don't need any rounding, as they may naturally fall on a whole number or precise cent, such as \(17 from the \(85 \times 0.20\) calculation.

However, if you encounter a value such as \)17.456, you would round to $17.46. The rule to remember is:

• If the digit after your rounding point is less than 5, you round down.


• If it is 5 or greater, round up.

This standard rounding process helps to ensure clarity and accuracy in financial transactions.