Understanding percentages is really important for figuring out sales tax when we buy things every day. Let’s break it down:

1. Calculating Total Costs: When we buy something, the price we see usually doesn’t include sales tax.

   For example, if a pair of shoes costs $100 and the sales tax is 20%, we have to add that sales tax to the price. Here’s how we figure it out:

   To find the sales tax, we multiply the price by the tax rate like this:

   $\text{Sales Tax} = \text{Price} \times \left( \frac{\text{Tax Rate}}{100} \right)$

   So for our shoes, it would look like this:

   $\text{Sales Tax} = 100 \times \left( \frac{20}{100} \right) = 20$

   This means that at the store, we end up paying $120!

2. Understanding Value for Money: Knowing how to calculate percentages helps us decide where to shop. Different stores can have different sales tax rates.

   For instance, one store might charge 10% sales tax on clothing, while another store has 15% for electronics. If we calculate the total cost, including tax, we can choose the best place to shop based on how much we’ll actually spend.

3. Budgeting: When we plan how to spend our money, it's smart to include sales tax in our budget. If you're saving up for something big, knowing that sales tax is a percentage of the price can help avoid unexpected costs.

In summary, understanding percentages helps us make smarter choices when we shop. It ensures we know exactly how much money we’ll need to spend in total!