Common Mistakes in Changing Percentages and Decimals

Sometimes, people get confused when switching between percentages and decimals. Let’s make it easier to understand.

1. What is a Percentage?
   A percentage means "out of 100." For example, $25\%$ means $25$ out of $100$. This is the same as the decimal $0.25$.

2. How to Change Them:

   • To change a percentage to a decimal, you divide by $100$. For example, to change $75\%$ to a decimal:
     $75\% = \frac{75}{100} = 0.75$

   • To change a decimal to a percentage, you multiply by $100$.
     For instance:
     $0.4 \times 100 = 40\%$

3. Common Mistakes to Watch Out For:

   • Decimal Places: Some students forget to move the decimal point. Remember, for percentages to decimals, move the point two places to the left. For decimals to percentages, move it two places to the right.

   • Mixing Up Steps: Sometimes, students might switch the steps by mistake. For example, they might think $0.85$ is $85\%$ when it's actually already $85\%$.

By practicing these methods, students can dodge these common mistakes and do great in their math work!