Percentages - Free maths worksheets and other resources - Free Printable

Problem Overview:

The task involves calculating percentages of given numbers. Specifically, you need to find 10%, 20%, 30%, 5%, and 15% of the following amounts: 30, 90, 60, 20, 100, and 70.

Solution Approach:

To calculate a percentage of a number, use the formula:
\[
\text{Percentage of a number} = \left( \frac{\text{Percentage}}{100} \right) \times \text{Number}
\]

For example:
- To find 10% of 30:
\[
10\% \text{ of } 30 = \left( \frac{10}{100} \right) \times 30 = 0.1 \times 30 = 3
\]

We will apply this formula systematically for all the required calculations.

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Step-by-Step Calculations:

#### 1. Find 10% of the following amounts:
1. \( 10\% \text{ of } 30 = \left( \frac{10}{100} \right) \times 30 = 0.1 \times 30 = 3 \)
2. \( 10\% \text{ of } 90 = \left( \frac{10}{100} \right) \times 90 = 0.1 \times 90 = 9 \)
3. \( 10\% \text{ of } 60 = \left( \frac{10}{100} \right) \times 60 = 0.1 \times 60 = 6 \)
4. \( 10\% \text{ of } 20 = \left( \frac{10}{100} \right) \times 20 = 0.1 \times 20 = 2 \)
5. \( 10\% \text{ of } 100 = \left( \frac{10}{100} \right) \times 100 = 0.1 \times 100 = 10 \)
6. \( 10\% \text{ of } 70 = \left( \frac{10}{100} \right) \times 70 = 0.1 \times 70 = 7 \)

#### 2. Find 20% of the following amounts:
1. \( 20\% \text{ of } 30 = \left( \frac{20}{100} \right) \times 30 = 0.2 \times 30 = 6 \)
2. \( 20\% \text{ of } 90 = \left( \frac{20}{100} \right) \times 90 = 0.2 \times 90 = 18 \)
3. \( 20\% \text{ of } 60 = \left( \frac{20}{100} \right) \times 60 = 0.2 \times 60 = 12 \)
4. \( 20\% \text{ of } 20 = \left( \frac{20}{100} \right) \times 20 = 0.2 \times 20 = 4 \)
5. \( 20\% \text{ of } 100 = \left( \frac{20}{100} \right) \times 100 = 0.2 \times 100 = 20 \)
6. \( 20\% \text{ of } 70 = \left( \frac{20}{100} \right) \times 70 = 0.2 \times 70 = 14 \)

#### 3. Find 30% of the following amounts:
1. \( 30\% \text{ of } 30 = \left( \frac{30}{100} \right) \times 30 = 0.3 \times 30 = 9 \)
2. \( 30\% \text{ of } 90 = \left( \frac{30}{100} \right) \times 90 = 0.3 \times 90 = 27 \)
3. \( 30\% \text{ of } 60 = \left( \frac{30}{100} \right) \times 60 = 0.3 \times 60 = 18 \)
4. \( 30\% \text{ of } 20 = \left( \frac{30}{100} \right) \times 20 = 0.3 \times 20 = 6 \)
5. \( 30\% \text{ of } 100 = \left( \frac{30}{100} \right) \times 100 = 0.3 \times 100 = 30 \)
6. \( 30\% \text{ of } 70 = \left( \frac{30}{100} \right) \times 70 = 0.3 \times 70 = 21 \)

#### 4. Find 5% of the following amounts:
1. \( 5\% \text{ of } 30 = \left( \frac{5}{100} \right) \times 30 = 0.05 \times 30 = 1.5 \)
2. \( 5\% \text{ of } 90 = \left( \frac{5}{100} \right) \times 90 = 0.05 \times 90 = 4.5 \)
3. \( 5\% \text{ of } 60 = \left( \frac{5}{100} \right) \times 60 = 0.05 \times 60 = 3 \)
4. \( 5\% \text{ of } 20 = \left( \frac{5}{100} \right) \times 20 = 0.05 \times 20 = 1 \)
5. \( 5\% \text{ of } 100 = \left( \frac{5}{100} \right) \times 100 = 0.05 \times 100 = 5 \)
6. \( 5\% \text{ of } 70 = \left( \frac{5}{100} \right) \times 70 = 0.05 \times 70 = 3.5 \)

#### 5. Find 15% of the following amounts:
1. \( 15\% \text{ of } 30 = \left( \frac{15}{100} \right) \times 30 = 0.15 \times 30 = 4.5 \)
2. \( 15\% \text{ of } 90 = \left( \frac{15}{100} \right) \times 90 = 0.15 \times 90 = 13.5 \)
3. \( 15\% \text{ of } 60 = \left( \frac{15}{100} \right) \times 60 = 0.15 \times 60 = 9 \)
4. \( 15\% \text{ of } 20 = \left( \frac{15}{100} \right) \times 20 = 0.15 \times 20 = 3 \)
5. \( 15\% \text{ of } 100 = \left( \frac{15}{100} \right) \times 100 = 0.15 \times 100 = 15 \)
6. \( 15\% \text{ of } 70 = \left( \frac{15}{100} \right) \times 70 = 0.15 \times 70 = 10.5 \)

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Final Answers:

\[
\boxed{
\begin{array}{ll}
\text{10\%:} & 3, 9, 6, 2, 10, 7 \\
\text{20\%:} & 6, 18, 12, 4, 20, 14 \\
\text{30\%:} & 9, 27, 18, 6, 30, 21 \\
\text{5\%:} & 1.5, 4.5, 3, 1, 5, 3.5 \\
\text{15\%:} & 4.5, 13.5, 9, 3, 15, 10.5 \\
\end{array}
}
\]