Question

Find each result without using a grid. \(30 \%\) of 15

Short answer

4.5

Step-by-step solution

Understand the Problem

We need to find 30% of 15. To do this, we can convert the percentage to a decimal and then multiply it by 15.

Convert Percentage to Decimal

Convert 30% to a decimal. To convert a percentage to a decimal, divide by 100. \( 30\text{\text{%}} = \frac{30}{100} = 0.3 \)

Multiply the Decimal by the Number

Multiply the decimal (0.3) by 15: \( 0.3 \times 15 = 4.5 \)

Write the Result

So, 30% of 15 is 4.5.

Key concepts

Converting Percentages to Decimals

Understanding how to convert percentages to decimals is crucial for solving many math problems. A percentage is a way to express a number as a fraction of 100. For example, 30% means 30 out of 100. To convert a percentage into a decimal, you simply divide by 100.

Consider the given exercise where we need to find 30% of 15. The first step is to convert 30% into a decimal.

• Divide 30 by 100
• This gives us 0.3

To make it even clearer, you could think of moving the decimal point two places to the left. So, 30.0% becomes 0.30.

This small step of conversion makes further calculations easier and sets the stage for the multiplication process.

Basic Multiplication

Once you've converted the percentage to a decimal, the next step is multiplication. Multiplying a whole number by a decimal follows the same rules as regular multiplication.

In our example, we converted 30% to 0.3. The next step is to multiply this decimal by the given number, 15.

• 0.3 (decimal) × 15 (whole number)
• The result is 4.5

Breaking it down, imagine the decimal point isn't there:

• Imagine multiplying 3 by 15, which gives 45
• Since the original number was 0.3, we place the decimal point one position to the left, resulting in 4.5

Understanding this can help with a lot of math operations where decimals come into play.

Step-by-Step Math Problems

Approaching math problems step-by-step ensures you don't miss any vital details. For the problem of finding 30% of 15, breaking it down into manageable steps simplifies the process. Let's recap the steps:

• Step 1: Understand the Problem
• Step 2: Convert the Percentage to a Decimal
• Step 3: Multiply the Decimal by the Number
• Step 4: Write the Result

This methodical approach helps you keep track of what you're doing, ensures you're using the right operations, and makes it easier to identify where you might have gone wrong if the answer doesn't seem correct.

For our problem, by following these steps, we reach the correct result: 30% of 15 is 4.5.

Practicing these steps with different problems will reinforce your understanding of percentage calculations and basic multiplication.