Classroom · Economics
Identical crates, open prices, and nowhere to hide.
Two firms choose prices for identical crates. The lower price serves demand; tied firms split whole units equally, leaving any remainder unsold. Play two rounds, inspect sales and profits, then test whether a different permitted price would have paid more.
- In pairs
- About 20 min
- 2 acts
A practice run with fictional students. No real classroom or join code is created.
Try an answer on the phone. Lead the lesson from the screen.
On their phone
You are presenting
Setting up the room…
Lesson deck
Teach it as a ready-made lesson
Hook, how it works, the live game and takeaways. Edit anything.
Same crate, same street
A ready-to-teach lesson deck: a hook, how it works, the live game and takeaways for the debrief.
6 slides · 1 activity
What it teaches
Compare price competition with quantity competition while holding the stock demand and cost assumptions fixed. The textbook price-at-cost result is a theoretical reference, not a prediction that two classroom rounds must reach it. Students test unilateral price changes against their rival’s actual price, accounting for this game’s whole-pound prices, whole-unit demand and tie rule.
- Price competition
- Marginal cost
Debrief, while the boards are still up
- 01
Which firms sold units, and which did not? With the rival’s price fixed, would a permitted undercut, tie or price increase improve your profit?
- 02
How did your prices compare with marginal cost? If you also played Cournot, what changed in the decisions and outcomes, and what stayed the same?
- 03
Could whole-pound price steps or the unsold tie remainder affect a best response? What might change with differentiated products or different demand?
How it works
- 01
Add it to your library
Sign up free and pull the activity from Decka's built-in classroom catalog — one click copies it into your own library, ready to run from Decka or inside PowerPoint.
- 02
Students join by QR
Everyone scans from the projector and plays in their phone's browser. No app, no account, nothing to install.
- 03
You run the room
You move the activity phase by phase: collection closes, the boards resolve on the big screen, and the debrief happens while the results are still up.
What is the Bertrand game?
Bertrand competition changes the firms’ choice from quantity to price. For identical goods, the lower-priced firm serves the market’s demand. The familiar continuous-price model uses this undercutting incentive to explain the price-at-marginal-cost benchmark. This classroom version uses discrete prices and quantities, so check the permitted alternatives rather than treating that benchmark as its only possible outcome.
The stock activity pairs firms for two rounds with demand Q = max(0, floor((100 − price) / 1)) and a production cost of twenty pounds per crate. Prices are whole pounds from zero to one hundred. If both firms name the lowest price, each sells the same whole-number share of demand; an odd leftover unit remains unsold. Profit is (price − unit cost) × units sold, so sales below cost can lose money. The boards reveal the markets that settled, not a predetermined price war; a market missing a firm’s decision is not settled by inventing an answer.
FAQ
Bertrand game questions, answered
What happens when both firms set the same price?
They divide demand equally in whole units, with any remainder unsold. For example, at the stock price of twenty-one pounds, demand is seventy-nine crates: each tied firm sells thirty-nine and one crate remains unsold. Compare the profit from a permitted undercut, not just its higher sales volume.
Why do the numbers match the Cournot game?
The stock versions share the demand intercept, slope and production cost. One asks firms for quantities; the other asks for prices. That gives a useful classroom comparison, but it does not guarantee different prices or make two class sessions a controlled empirical experiment. Check any teacher-customized assumptions before comparing them.
Is the price really expected to hit cost?
No classroom outcome is guaranteed. Price at marginal cost is the textbook reference, and this game’s price grid and tie rounding matter when checking a deviation. An above-cost result alone does not establish tacit collusion. Compare the actual decisions and test whether either firm could earn more by changing only its permitted price.
Do students need an app or an account?
No. Students scan a QR code from the projector (or open a link) and play in their phone's browser. Nothing to install and nothing to sign up for.
Does it work in PowerPoint or Google Slides?
In PowerPoint, yes: open the Decka add-in on a slide and choose the Classroom tile. Google Slides is not supported yet; there you present from Decka itself. Students play from their phones either way.
How many students can play at once?
Up to 50 participants per live activity on the free plan, 150 on Pro, and 300 on Badass.
More economics games to run live
- Closing time at the market
- You are the market
- Who really pays a tax?
- Two factories, one market, and the price you both set
- One of you builds the factory first
- Send it and see what comes back
- Ten coins and nobody can stop you
- One lot, and the best loser sets the price
- Spend the neighbourhood fund
- Four boats and a bay that belongs to nobody
- What is a flat worth to you?
- Three cars on one forecourt
- Tenants and landlords
- All economics activities
Ready to make your
presentations interactive?
Start free. No credit card required.