Tax and Tip
5 min
Teacher Prep
Setup
Narrative
The purpose of this Warm-up is to introduce students to the meaning of sales tax, which will be useful when students calculate prices including tax in a later activity. While students may notice and wonder many things about this situation, the important discussion point is why the total price is more than the price tag.
This Warm-up prompts students to make sense of a problem before solving it by familiarizing themselves with a context and the mathematics that might be involved (MP1).
Launch
Arrange students in groups of 2. Display the image for all to see. Ask students to think of at least one thing they notice and at least one thing they wonder. Give students 1 minute of quiet think time and then 1 minute to discuss the things they notice and wonder with their partner.
Student Task
You are on vacation and want to buy a pair of sunglasses for $10 or less. You find a pair with a price tag of $10. The cashier says the total cost will be $10.45.
What do you notice? What do you wonder?
Sample Response
Students may notice:
- The price of the sunglasses is $10.
- The total cost is more than the price of the sunglasses.
- Sales tax was added to the cost of the sunglasses.
Students may wonder:
- If the cashier made a mistake.
- Why the total cost is more than the price listed on the sunglasses.
- What the tax is on the sunglasses.
- If something else was purchased to make the price more.
Activity Synthesis (Teacher Notes)
Ask students to share the things they noticed and wondered. Record and display their responses without editing or commentary. If possible, record the relevant reasoning on or near the image. Next, ask students, “Is there anything on this list that you are wondering about now?” Encourage students to observe what is on display and respectfully ask for clarification, point out contradicting information, or voice any disagreement.
If questioning why the total price is higher than the price tag does not come up during the conversation, ask students to discuss this idea. Ask students if they have ever heard of sales tax before, and if some have, ask them to share their understanding.
Explain that sales tax is a fee (an amount of money) paid to the government. The amount of tax is a percentage of the price of the item. Different states charge different sales tax percentages, and additionally some local governments, like for counties and cities, also charge a sales tax.
To start to help make sense of how sales tax works, ask questions like:
- ”How much sales tax is being collected on the $10 sunglasses?” ($0.45 or 45 cents)
- ”45 cents is what percent of $10?” (4.5%)
- ”What is the sales tax rate for our local area?” (Answer varies based on location.)
Standards
- 7.RP.3·Use proportional relationships to solve multistep ratio and percent problems.
- 7.RP.A.3·Use proportional relationships to solve multistep ratio and percent problems. <span>Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.</span>
20 min
15 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Tax and Tip
5 min
Teacher Prep
Setup
Narrative
The purpose of this Warm-up is to introduce students to the meaning of sales tax, which will be useful when students calculate prices including tax in a later activity. While students may notice and wonder many things about this situation, the important discussion point is why the total price is more than the price tag.
This Warm-up prompts students to make sense of a problem before solving it by familiarizing themselves with a context and the mathematics that might be involved (MP1).
Launch
Arrange students in groups of 2. Display the image for all to see. Ask students to think of at least one thing they notice and at least one thing they wonder. Give students 1 minute of quiet think time and then 1 minute to discuss the things they notice and wonder with their partner.
Student Task
You are on vacation and want to buy a pair of sunglasses for $10 or less. You find a pair with a price tag of $10. The cashier says the total cost will be $10.45.
What do you notice? What do you wonder?
Sample Response
Students may notice:
- The price of the sunglasses is $10.
- The total cost is more than the price of the sunglasses.
- Sales tax was added to the cost of the sunglasses.
Students may wonder:
- If the cashier made a mistake.
- Why the total cost is more than the price listed on the sunglasses.
- What the tax is on the sunglasses.
- If something else was purchased to make the price more.
Activity Synthesis (Teacher Notes)
Ask students to share the things they noticed and wondered. Record and display their responses without editing or commentary. If possible, record the relevant reasoning on or near the image. Next, ask students, “Is there anything on this list that you are wondering about now?” Encourage students to observe what is on display and respectfully ask for clarification, point out contradicting information, or voice any disagreement.
If questioning why the total price is higher than the price tag does not come up during the conversation, ask students to discuss this idea. Ask students if they have ever heard of sales tax before, and if some have, ask them to share their understanding.
Explain that sales tax is a fee (an amount of money) paid to the government. The amount of tax is a percentage of the price of the item. Different states charge different sales tax percentages, and additionally some local governments, like for counties and cities, also charge a sales tax.
To start to help make sense of how sales tax works, ask questions like:
- ”How much sales tax is being collected on the $10 sunglasses?” ($0.45 or 45 cents)
- ”45 cents is what percent of $10?” (4.5%)
- ”What is the sales tax rate for our local area?” (Answer varies based on location.)
Standards
- 7.RP.3·Use proportional relationships to solve multistep ratio and percent problems.
- 7.RP.A.3·Use proportional relationships to solve multistep ratio and percent problems. <span>Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.</span>