- Third Grade
- 60 minutes
- Standards: 3.OA.C.7
Teach your youngsters the art of savvy shopping with this neat lesson on calculating price per item. After doing some division problems to compare the values of different products, students put their skills to the test with fun worksheets.
Students will be able to use basic division to calculate the price per item in a package.
Introduction (5 minutes)
- Activate prior knowledge by allowing a student to share a time she purchased something from a store.
- Ask students if they were concerned about getting the most for the money they spent. Did they compare different brands of the same product before buying?
- Explain to the class they are going to use basic division facts to make sure they get the most for their money the next time they go to the store.
Explicit Instruction/Teacher Modeling (5 minutes)
- Show the price tagged items.
- Ask students if they understand the effect of bulk, or high-quantity, packaging on the price of an item.
- Ask them what they think has better value—the various items or the item in a bulk package.
- Let students know they will be given an opportunity to prove or disprove their answer, using basic division facts.
Guided Practice/Interactive Modeling (20 minutes)
- Give each student a calculator, then briefly demonstrate how to use it.
- Show the students the first single item and its cost. Explain to students how a change in portions affects the cost of a single item.
- Explain the parts of a division problem: divisor, dividend, quotient.
- Write the following formula on the board: price ÷ number of items = price per item. Explain that students will be using this formula to solve division problems. They'll need to calculate the price per item for a few of the single items.
- Allow students to come up in groups of 3-4 at a time to make calculations.
- Write down the price per item values on the board as students find them.
- Once students are done, calculate and write down the price per item value of the bulk item.
- Give the class some time to discuss the correct answer (that the bulk package has a lower price per item) and compare it to their original impressions.
Independent Working Time (15 minutes)
- Hand out a School Shopping worksheet and set of Play Money cutouts to each student.
- Allow students to use their play money and calculators to complete the worksheet. However, make sure they show their work.
- Enrichment: Have advanced students complete their calculations without calculators, but allow them to go back check their work with calculators.
- Support: Pair struggling students with more advanced students. During Independent practice, allow these students to use play money while their partners use calculators. Each struggling student can practice using the calculator as her partner records the information.
Related Books and/or Media
Assessment (10 minutes)
- Ask students some questions about the lesson. Examples are: Which did you originally guess would be the cheapest portion? Was that the cheapest portion? Why was that portion the cheapest?
- Have them write down their answers on the backs of their worksheets.
- Collect the sheets once they're finished, and review them later to assess student comprehension.
Review and Closing (5 minutes)
- Review the formula used to calculate price per item.