Calculating discounts is a common task in everyday life, whether you're shopping for clothes, electronics, or groceries. Understanding how to calculate percentages quickly can save you time and money. This article will walk you through how to figure out what 10% off of 45 is, and provide some handy methods for calculating similar discounts.
Understanding Percentage Discounts
A percentage discount represents a fraction of the original price. "10% off 45" means we need to find 10% of 45 and then subtract that amount from the original price of 45.
Method 1: Calculating 10% Directly
The easiest way to calculate 10% of a number is to move the decimal point one place to the left.
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Step 1: To find 10% of 45, move the decimal point in 45.0 one place to the left. This gives you 4.5.
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Step 2: Subtract this amount (4.5) from the original price (45).
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45 - 4.5 = 40.5
Therefore, 10% off of 45 is
Method 2: Using the Decimal Equivalent
Percentages can also be expressed as decimals. 10% is equivalent to 0.10.
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Step 1: Multiply the original price (45) by the decimal equivalent of 10% (0.10): 45 * 0.10 = 4.5
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Step 2: Subtract the result (4.5) from the original price (45): 45 - 4.5 = 40.5
Again, 10% off of 45 is
Method 3: Finding 10% and Subtracting Mentally
For a 10% discount, you can often perform the calculation mentally.
Think of it this way: 10% is one-tenth. One-tenth of 45 is 4.5. Subtracting 4.5 from 45 gives you 40.5.
This mental calculation method is particularly useful for quick estimations while shopping.
Applying This to Other Discounts
The methods above can be adapted to calculate other percentage discounts. For example, to find 20% off of 45:
- Method 1 (Decimal): 45 * 0.20 = 9; 45 - 9 = 36
- Method 2 (Fraction): 20% is one-fifth; one-fifth of 45 is 9; 45 - 9 = 36
Conclusion
Calculating a 10% discount, or any percentage discount, is straightforward. By understanding the different methods, you can quickly and accurately determine the final price after a discount. Remember to practice these techniques so you can confidently calculate discounts in various situations. Now you know exactly what 10% off of 45 is – it's 40.5!
