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Percentages – Decimals to percentages

📘 Notes

Decimals to Percentages (Year 7)

To change a decimal into a percentage, multiply it by 100 and write the percent symbol (%).

1. Multiply by 100%

Rule:

\[ \text{Decimal} \times 100\% = \text{Percentage} \]

Example: \(0.75\)

\[ 0.75 \times 100\% = 75\% \]

Example: \(0.08\)

\[ 0.08 \times 100\% = 8\% \]

2. Move the Decimal Point

Shortcut: Moving the decimal point 2 places to the right is the same as multiplying by 100.

Decimal Move 2 places Percentage
0.33030%
0.565656%
1.25125125%

3. Whole Numbers with Decimals

If the number is greater than 1, the percentage will be more than 100%.

Example: \(1.2\)

\[ 1.2 \times 100\% = 120\% \]

Example: \(2.5\)

\[ 2.5 \times 100\% = 250\% \]

4. Quick Tips

  • Multiply by 100 and add the % sign.
  • Move the decimal point two places to the right.
  • Numbers bigger than 1 become more than 100%.
  • Small decimals become small percentages.

5. Try These

  1. 0.45
  2. 0.09
  3. 1.8
  4. 0.007
  5. 2.36

Convert each decimal into a percentage.