What is 20% of 40?

NOVEMBER 24, 2023

What is 20% of 40?

Answer:

The answer is 8.

Method: Hints

To find 20% of 40, we can follow these steps:

  1. Understand the Percentage: The word 'percent' means 'per hundred'. So, when we are looking for 20% of a number, we are looking for 20 per every 100 units of that number.

  2. Convert Percentage to Decimal: To make the calculation easier, we convert the percentage to a decimal. To do this, we divide the percentage by 100. Thus, 20% becomes 0.20.

    $$ \text{Decimal form of 20%} = \frac{20}{100} = 0.20 $$

  3. Multiply by the Number: Now, we multiply the decimal form of the percentage by the number we want to find the percentage of. In this case, it's 40.

    $$ 0.20 \times 40 $$

  4. Perform the Calculation: Carry out the multiplication.

    $$ 0.20 \times 40 = 8 $$

  5. Conclusion: Therefore, 20% of 40 is 8.

Verification

To ensure the answer is correct, we can check the calculation:

  • We know that 10% of 40 is 4 (since 10% is one-tenth of 100, and thus one-tenth of 40 is 4).
  • Since 20% is double 10%, we double our previous result: 4 * 2 = 8.
  • This confirms that our answer of 8 is correct.

Related Knowledge Points and Detailed Explanation

  • Percentages: Percentages are a way of expressing a number as a fraction of 100. They are widely used in various fields, such as finance, statistics, and general mathematics.

  • Decimal Conversion: Converting a percentage to a decimal is a crucial step in percentage calculations and is done by dividing the percentage by 100.

  • Multiplication: Multiplication is one of the basic operations in arithmetic. When we multiply a decimal by a whole number, we are essentially finding a portion of the whole number.

  • Checking Work: It's always good practice to check your work in mathematics. By using related knowledge (like knowing what 10% of a number is), we can quickly verify our results.

In conclusion, understanding how to calculate percentages is a fundamental math skill that can be applied in various real-world situations. By converting percentages to decimals and multiplying by the number in question, we can easily find the required percentage of any given number.