Math Class: Dining Out

Ms. Lynne Bailey ~ Student Guide ~ Download the Teacher Guide & Worksheet


How do we calculate every day percentages?
How do we use estimates when shopping?

Essential Questions for Dinner Conversation:

  • Why do we pay gratuities? Why would some restaurants add it to the bill?
  • Why do we pay taxes?
  • What are they
    used for?
  • Do you think taxes are fair? Why or why not?
  • Wikipedia articla about Sales Tax 

Discuss this while you are waiting for your bill, or while you are waiting to take the food order.

Jot down your group's answer to share with the class later.

Contest & Check Evaluation:

Contest: Group with check closet to $50.00 without going over wins dessert!

Check total equals $47.50 - $50.01:
(5) Totally Terrific

Check total equals $45.00 - $47.49:
(4) Pretty Close

Check total equals $40.00 - $44.00:
(3) Almost There

Check total equals $50.01 - $52.50:
(2) Skip Dessert

Check total over $52.50 or below $40.00:
(1) Do-over (homework)

Warm Up: Work in Groups of 3 (5-10 minutes)

Calculate the following using estimating techniques without using a calculator (try doing it 'in your head'):

  • What is 8 3/8% of 31? [x=.08375*31]
  • What is 17% of 34?

Write down your estimates and answer, and compare it with the classmates in your group.

Using a calculator, figure the exact answer. How close were your estimates to the exact answer? How did your estimating techniques differ from each other?

Just the Facts: Class Discussion (5 minutes)

  • What is a sales tax? What is the sales tax rate (%) in New York City?
  • What is a gratuity? What guidelines are used to calculate a gratuity in a restaurant?

In Groups of Three:
Today's Situation (30 minutes)

You and your friend are having dinner at a restaurant. You have a $50 gift certificate to use and just enough money to get home. You will not get any change from the gift certificate. Using the menus, choose items for you meal. If you go over $50, you'll have to wash dishes and walk home! Be sure to spend at least $40 and try to get as close to $50 without going over.


One student from each group will act as a server, and give menus to the other 2 students. The diners will have 10 minutes to make their selections. Your objective is get as close to $50 as possible, without going over. You don't have calculators with you, but you do have a pen & paper. You'll have to figure in NYC sales tax and a 17.5% gratuity will be added to your bill.

NOTE: The gratuity is added to the food total only, not the food plus the sales tax.

Servers will work in a separate group and discuss the essential questions while waiting for the diners to make their selection.

After 10 minutes, the server will take the order from the diners.

Diners will discuss the essential questions while waiting for their check. (Sorry - no food in class!)

Using a calculator, servers will figure the check for the diners (10 minutes) and deliver them. As a group, review the check to make sure it is correct. (5 minutes)

Summary 5 - 10 minutes

Review NYC Sales Tax Rate, Gratuities and Calculation

Each group shares their responses to the essential questions dinner conversation.

Congratulate the group that got closet to $50 without going over, and thank our servers for taking the orders.

Tomorrow's Lesson

How could we create an equation to figure this out?  Why would we want to do that?