Educational material from 
What you will learn
- Calculate each part of a portfolio before adding the parts together.
- Distinguish an amount in kronor from return and weight as percentages.
- Explain why a winner in an invented scenario is not a general investment rule.
Session plan: 35 minutes, without an app account
Give students the table below and a calculator. Spend five minutes reading the assumptions, fifteen calculating in pairs, ten comparing methods and five writing an individual closing question. All amounts, companies and changes are invented. Nobody buys securities or deposits money.
This task differs from the open lesson idea on the schools page: the starting allocations are fixed and everyone calculates two scenarios. That makes it easier to identify which calculation step needs explanation. Students need to understand a percentage as a share of one hundred; they can read the portfolio-weights concept lesson before the session.
Worksheet: use the same price changes
Both portfolios begin at SEK 10,000. Group One has more in company A and Group Two more in company B. Cash is unchanged. We leave out fees, tax, dividends and currency effects. No money is added or withdrawn during the activity.
In scenario 1, A falls 10 percent while B rises 20 percent. Calculate the values of A, B and cash, add them to find the ending value and calculate the percentage change from SEK 10,000. Then calculate A's new weight as its ending value divided by the portfolio's new total.
In scenario 2, restart from the starting table: A instead rises 20 percent and B falls 10 percent. Scenario 2 does not continue from scenario 1. Compare the results and write one sentence about how allocation affects the outcome.
If the table does not fit, scroll it sideways.
| Part | Group One | Group Two |
|---|---|---|
| Company A | SEK 6,000 (60 %) | SEK 2,000 (20 %) |
| Company B | SEK 2,000 (20 %) | SEK 6,000 (60 %) |
| Cash | SEK 2,000 (20 %) | SEK 2,000 (20 %) |
| Total | SEK 10,000 | SEK 10,000 |
Answer key: check the parts before the total
For Group One in scenario 1, A becomes 6,000 × 0.90 = SEK 5,400 and B becomes 2,000 × 1.20 = SEK 2,400. With SEK 2,000 in cash, the total is SEK 9,800. The change is −200 ÷ 10,000 × 100 = −2 percent. A's new weight is 5,400 ÷ 9,800 × 100, approximately 55.1 percent.
For Group Two in the same scenario, A becomes SEK 1,800 and B SEK 7,200. The total is SEK 11,000, equivalent to +10 percent. A's new weight is approximately 16.4 percent. In scenario 2, the ending values are instead SEK 11,000 for Group One and SEK 9,800 for Group Two. Reversing the price movements changes which group has the higher ending value.
If the table does not fit, scroll it sideways.
| Answer | Group One | Group Two |
|---|---|---|
| A after the change | SEK 5,400 | SEK 1,800 |
| B after the change | SEK 2,400 | SEK 7,200 |
| Total | SEK 9,800 | SEK 11,000 |
| Change | −2 % | +10 % |
| A's new weight | 55.1 % | 16.4 % |
Teacher notes: use mistakes as clues
If a student answers +5 percent for both groups, they probably averaged the stocks' −10 and +20 percent changes. Ask how many kronor each change applies to. If a student says A still weighs 60 percent in Group One, ask them to compare the starting total with the new total.
Ask students to explain both scenarios before drawing a conclusion about allocation. Assess whether they state assumptions, use the correct base in the percentage calculation and explain the difference between an outcome and a general rule. The task shows the effect of allocation; it does not say which of the two portfolios anyone should choose in real life.
Finish by asking each student to create a scenario in which both companies fall. Discuss what the cash portion does in this particular model and which real-world factors the model left out. To continue, use the lesson idea on the schools page or read the product guide about virtual portfolios.
Student and teacher sheets for printing
The same activity is available as separate sheets: a student worksheet with blank answer spaces and teacher notes with the answers. Open the sheet you need and use your browser’s print function. The sheets have an A4 layout and require no app account.
Give students the student worksheet and keep the teacher sheet for the discussion. The complete session plan, sources and digital follow-up remain on this page.
Try it yourself
Restart from the starting table. Let both A and B fall 10 percent while cash remains unchanged. What are the ending value and percentage change for each group?
Show the solution and explanation
Both groups finish with SEK 9,200, a change of −8 percent.
Both hold SEK 8,000 in stocks. A 10 percent fall reduces that portion by SEK 800; the SEK 2,000 in cash remains. The different allocation between A and B makes no difference when both experience the same percentage change.
Check your understanding
Why should scenario 2 restart from the starting table?
That compares two alternative outcomes with the same starting point. Continuing from scenario 1 would instead produce a sequence of changes and a different task.
Which total do you use for a new weight?
The total after the price changes. For Group One in scenario 1, it is SEK 9,800 rather than the SEK 10,000 starting value.
Practise with virtual money
Try what you just learned in a practice portfolio with virtual money. You don't deposit any real money.
How the practice portfolio worksKeep learning and practising
More activities on this topic
Calculate, interpret and evaluate sources
- Money and percentages: a classroom worksheet with answers
- Read a stock chart in class: three claims and an answer key
- Stock splits and new shares: ownership cards for the classroom
- Inflation and purchasing power: a classroom basket worksheet
- Stock order fees: a classroom worksheet and cash-flow answers
- A paper stock-market game: two rounds, student journal and answers
Sources and examples
The sources support the factual explanations. Calculations and exercises were created for this lesson. Amounts and price changes are invented unless stated otherwise.
This material is educational and does not recommend securities to buy. A simulated result does not guarantee a future result.
