2 × $3.00 + 1 × $4.00 + 10 × $2.00
Free classroom kit
Why can inflation fall while prices remain high?
A complete lesson that helps students calculate a simple price basket, distinguish the inflation rate from the price level, and explain why slower inflation does not reverse earlier price increases.
01
Teacher guide
Start with the distinction students need.
Core explanation
Inflation is a rate of change. The price level is the amount prices have reached. When inflation falls but remains positive, the price level continues to rise at a slower rate.
Learning objectives
Standards alignment: Council for Economic Education National Content Standards in K through 12 Economics, Standard 15: Inflation.
By the end of the lesson, students should be able to:
- Distinguish the price level from the inflation rate.
- Calculate the cost of a fixed basket using quantities and prices.
- Calculate a percentage change between two basket costs.
- Explain why a falling positive inflation rate does not return prices to an earlier level.
- Name one reason a household experience can differ from a published average.
Lesson sequence
- 7 minutesIntroduce the distinction
Ask whether a car traveling more slowly is moving backward. Connect speed with the inflation rate and position with the price level.
- 12 minutesCalculate the basket
Students complete the fixed basket activity individually or in pairs.
- 8 minutesTest the claim
Students evaluate the statement that prices fell because inflation fell.
- 8 minutesDiscuss different experiences
Students compare how a household with different spending weights could experience a different rate.
Important teaching limit
The activity uses a fictional fixed basket to isolate the arithmetic. Official consumer price indexes use far more observations and account for weights, sampling, substitutions, quality changes, and other methodological issues.
02
Student activity
Calculate a simple price basket.
NameDate
A fictional classroom basket contains the same quantities in every year. For each item, multiply the quantity by its price. Then add the item costs to find the full basket cost.
| Item | Quantity | Year 1 price | Year 2 price | Year 3 price |
|---|---|---|---|---|
| Bread loaves | 2 | $3.00 | $3.30 | $3.36 |
| Milk cartons | 1 | $4.00 | $4.40 | $4.48 |
| Bus rides | 10 | $2.00 | $2.20 | $2.24 |
What does the full basket cost in Year 1?
What does the full basket cost in Year 2?
What does the full basket cost in Year 3?
Use this formula to calculate inflation from Year 1 to Year 2: new basket cost minus old basket cost, divided by old basket cost, multiplied by 100.
Calculate inflation from Year 2 to Year 3 using the same formula.
Did inflation rise or fall in Year 3? Did the basket become cheaper or more expensive?
How much higher is the Year 3 price level than the Year 1 price level?
Evaluate this statement: “Inflation fell in Year 3, so prices returned to their Year 1 level.” Use your calculations as evidence.
03
Teacher answer key
Show the arithmetic and the interpretation.
2 × $3.30 + 1 × $4.40 + 10 × $2.20
2 × $3.36 + 1 × $4.48 + 10 × $2.24
- Year 1 to Year 2 inflation is 10 percent.
The basket increased by $3.00. Dividing $3.00 by $30.00 gives 0.10.
- Year 2 to Year 3 inflation is about 1.8 percent.
The basket increased by $0.60. Dividing $0.60 by $33.00 gives about 0.018.
- Inflation fell, but the basket became more expensive.
The inflation rate slowed from 10 percent to about 1.8 percent. Because the rate stayed positive, the price level rose from $33.00 to $33.60.
- The Year 3 price level is 12 percent above Year 1.
The basket increased by $3.60 from the Year 1 level of $30.00. Dividing $3.60 by $30.00 gives 0.12.
- The quoted statement is false.
Falling inflation means the rate of increase slowed. The Year 3 basket cost of $33.60 remained above both earlier costs.
04
Extension activity
Show why household experience can differ.
Ask half the class to double the bread quantity and the other half to double the bus ride quantity. Recalculate each basket for every year and compare the results.
Why do the results differ?
A basket gives more influence to items with larger spending weights. Different quantities create different weights.
What does this reveal?
A published index summarizes a broad reference population. One household can spend differently and experience a different change.
What still remains simplified?
Actual indexes use many products, locations, observations, weights, and adjustments that this exercise intentionally leaves out.
05
Evidence and reuse
Keep the source record attached.
The basket values in this activity are fictional and were chosen to make the arithmetic visible. The definitions, interpretation guidance, and method limits are based on the official sources below.
- Council for Economic EducationStandard 15 defines inflation and sets grade appropriate expectations for price indexes, the inflation rate, and purchasing power.National Content Standards in K through 12 Economics
- United States Bureau of Labor StatisticsOfficial guidance about what the consumer price index measures and how to interpret it.Consumer Price Index Frequently Asked Questions
- United States Bureau of Labor StatisticsOfficial technical explanation of index calculation, weighting, aggregation, and adjustment.Calculation of the Consumer Price Index
- World BankInternational annual inflation observations and source documentation.Inflation, consumer prices
Reuse permission
Copy and adapt this resource with attribution.
This original classroom material is available under the Creative Commons Attribution 4.0 International license. Official source material remains subject to its own terms.
Suggested attribution
World Economy. Inflation lesson plan and classroom activity. https://losttofound.org/classroom/inflation. Creative Commons Attribution 4.0 International.
Questions for the project