When students work with percentages, they can make common mistakes that lead to confusion. Here are some things to watch out for:

1. Mixing Up Parts and Whole Numbers: Sometimes, students think that $20\%$ of $50$ is $20$ instead of $10$. To find $20\%$ of $50$, you multiply $50$ by $0.20$. When you do that, you get $10$.

2. Getting Percentage Increases and Decreases Wrong: If a student wants to increase a price of $200 by$10%$, they might mistakenly add$20$instead of the right amount. To correctly find$10%$of$200$, you multiply$200$by$0.10$, which gives you$20$. So, the new price would be$200 + 20 = 220$.

3. Forgetting the Original Amount: Sometimes, students forget to think about the original amount when calculating a percentage change. It’s important to always know what the starting number is before you apply the percentage.

By keeping an eye on these common mistakes, students can get better at working with percentages!