K-12 Teaching and Learning From the UNC School of Education


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Learning outcomes

Students will:

  • identify uses of technology in the community and how it has changed the ways we work and play.
  • respond to the teacher guided technology scenarios using a familiar occupation such as cashier, teller, librarian, waitress.
  • regroup/round/estimate single and double digit numbers.

As a group we will use problem solving strategies, calculator, and explain our solution to the problem.

Teacher planning

Time required for lesson

45 minutes


  • Area large enough and close enough for students to gather to see presentation on SmartBoard or Averkey
  • Grocery Store Items: doc | rtf
  • Paper and pencil
  • Calculator on computer

Technology resources

  • Computer connected to SmartBoard or Averkey.
  • Word processing program with Clipart or similar type program to create visual. The Kidspiration program could be used to create the visual.
  • Calculator on computer.


Students should have prior experience with single and double digit addition and subtraction, mental math, estimation, and rounding. Knowledge of monetary symbols (dollar sign and decimal) is helpful.


  1. Teacher displays the Grocery Store Items visual on the SmartBoard or Averkey then goes over each item and its price. Students are told they are going to discuss how the technology in an occupation (grocery store cashier) has changed.
  2. Students are asked to go back in time about 100 years ago to a general store. We want to purchase each item on our list. The grocer does not have a cash register or calculator because they haven’t been invented yet. Paper and pencil are too scarce to use. How would we and the grocer compute the cost of our groceries? (Using mental math, using our brain, counting on fingers are some appropriate answers.)
  3. Together we estimate the cost by rounding each item to the nearest dollar. Students are asked to add each rounded item mentally or on their fingers, the old fashioned way since we are back in time 100 years. Teacher leads the group by adding out loud and on fingers. Together we come up with an estimate of the cost. Is this the exact cost? No, because we rounded to the nearest dollar.
  4. Next we are in the neighborhood market, still before cash registers and calculators have been invented. How can the cashier add up our order and give us a written receipt to check over? (Mental math, brains, fingers are acceptable answers but paper and pencil is the answer you are trying to elicit.)
  5. Have all prices written down on a sheet of paper and lead the class through adding them up. Is this the exact cost? Yes, because we added the exact price of each item. Could we make a mistake? How? Add incorrectly, write a wrong price down are possible answers. How can we check this sum (answer in addition) today? Possible answers: use subtraction, add it again, or use a calculator.
  6. Teacher tells students that when she was their age, cashiers used cash registers. Cashiers actually had to enter each price into the cash register just like using a calculator. Did you know there is a calculator on the computer? Teacher then shows students how to get to the calculator on their computer. (Programs, Accessories, Calculator) Then the teacher demonstrates how to add the grocery store items using the calculator on the computer. Be sure to point out that since it is money we have to put in the decimal point. The teacher orally calls out the price and the calculator buttons to press. Then have the class call the prices (numerals, decimal and plus/equal)out loud with you.
    • Was my sum on paper correct? Yes.
    • If your mom sends you to the store with $10, do you have enough money to buy all the items? No. Why not?
    • If your mom sends you to the grocery store with $20, do you have enough money to buy all the items? Yes. Why?
  7. Finally, discuss today’s technology- Tell me what does the cashier do? How does the cashier add up the prices? The cashier scans each item. (In some stores you may scan your own groceries.) When scanned it not only adds up the price but keeps track of inventory. (Inventory- how many items have been sold and tells you when you are running low on something so you can order more.)
  8. Then briefly review each step in the technology of the grocery store by calling on students to discuss the technology - how the groceries were added up each time.
  9. Students are asked if they can think of other occupations where the technology has changed? Can they think of sports or play areas that have changed and how? This can be done orally or as a written assignment asking for 2 changes in technology. Teacher should give some examples.


Teacher assesses each step from students’ oral answers, participation in the mental/finger math, adding together aloud while the teacher demonstrates the calculator and the review at the end of class.

I encourage students to use words like technology, scan, calculator, mental math, occupation. Students’ use of these words (100%) is my assessment.

The final section for assessment is if the student can orally tell or write about an occupation/sport and give 2 changes or advancements in technology for it.

Supplemental information

There is a free 30 day trial for Inspiration or Kidspiration at Inspiration.com.


I also work with Exceptional Children and modified this for their use by rounding all the prices. EC Grocery: doc | rtf

  • Common Core State Standards
    • Mathematics (2010)
      • Grade 2

        • Measurement & Data
          • 2.MD.8 Solve word problems involving dollar bills, quarters, dimes, nickels, and pennies, using $ and ¢ symbols appropriately. Example: If you have 2 dimes and 3 pennies, how many cents do you have?
      • Grade 3

        • Operations & Algebraic Thinking
          • 3.OAT.8Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.3

North Carolina curriculum alignment

Computer Technology Skills (2005)

Grade 3

  • Goal 1: The learner will understand important issues of a technology-based society and will exhibit ethical behavior in the use of computer and other technologies.
    • Objective 1.01: Identify, discuss, and chart uses of technology in the community (e.g., farmers, grocery, restaurant, veterinarian, medical and emergency services). Strand -Societal/Ethical Issues

Mathematics (2004)

Grade 3

  • Goal 1: Number and Operations - The learner will model, identify, and compute with whole numbers through 9,999.
    • Objective 1.02: Develop fluency with multi-digit addition and subtraction through 9,999 using:
      • Strategies for adding and subtracting numbers.
      • Estimation of sums and differences in appropriate situations.
      • Relationships between operations.
    • Objective 1.06: Develop flexibility in solving problems by selecting strategies and using mental computation, estimation, calculators or computers, and paper and pencil.