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What Borrowing Costs

A 45-minute Grade 3 lesson on what an interest rate is and why lenders charge one.

What Borrowing Costs is a free 45-minute Grade 3 to Grade 5 social studies lesson plan for Common Core standard D2.Eco.10.3-5 — explain what an interest rate is. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.

Grade:
Grade 3 to Grade 5
Length:
45 minutes
Standard:
D2.Eco.10.3-5

Grade 3 to Grade 5 · Economics

D2.Eco.10.3-5

Explain what interest rates are.

Objective

Students will be able to explain what interest is, in both directions, and why a rate might differ between borrowers.

Students are successful when they can

  • Identifies interest as the price of borrowing.
  • Recognises interest paid to a saver.
  • Says why one borrower is charged more than another.

What you need

  • Worked figures: borrow 100, repay 105
  • A boatman's loan for a barge, dated 1845
  • The printable practice sheet linked at the end of this plan

The lesson

Warm-up — the extra five

5 min
  1. Borrow 100 pounds, repay 105. Ask what the extra five is for.
  2. Take the answers, including 'a fine'.

Teach — a price, both ways

15 min
  1. Name it: interest is the price of using somebody else's money.
  2. Ask why a lender charges anything. Because that money could have been used elsewhere meanwhile.
  3. Turn it round: save 100 and be paid 3. That is interest paid to you for lending.
  4. Define the rate: how much it costs as a share of what was borrowed.
  5. Ask why one borrower is charged more. Because one is less likely to repay.
  6. Take the 1845 boatman borrowing for a barge. Ask what happened to him in 1847.
“Whose money is being used, and what are they giving up while you use it?”

Guided practice — six cases

13 min
  1. Pairs decide, for six cases, who pays interest and who receives it.
  2. For two, they say why the rate would be high or low.
  3. Groups work out what a rising rate does to borrowing.

Independent practice

9 min
  1. Students complete the 'The Price of Borrowing' page.
  2. Check that interest is named as a price, not a punishment.

Close

3 min
  1. Ask why the railway company had to plan its fares around its loans.

What goes wrong, and why

Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.

Thinks interest is a penalty for borrowing.

Why: It looks like paying extra for a mistake.

Fix: It is a price, agreed in advance. A penalty comes from breaking something.

Thinks only borrowers meet interest.

Why: That is the memorable direction.

Fix: Savers receive it. Same idea, other side.

Thinks a higher rate means a greedier lender.

Why: Higher looks worse.

Fix: It usually means a riskier loan. Ask who is less likely to repay.

If they are not there yet

  • Three cases with the direction given.
  • Work only with the borrow-100-repay-105 example.

If they finish early

  • Work out what happens to borrowing if the rate rises from 3 to 8.
  • Say why the boatman's 1845 loan was riskier than it looked.
  • Explain why a rate is a share rather than a fixed sum.

Exit ticket

You save 100 pounds and are paid 3 pounds a year. What is the 3 pounds, and who is paying it?

What to look for: Interest, paid by the bank for the use of your money. Calling it a gift means the price idea has not landed.

Printable practice for D2.Eco.10.3-5

Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.

Questions about What Borrowing Costs

How long does the What Borrowing Costs lesson take?

45 minutes, split across 5 timed sections: warm-up 5 min, teach 15 min, guided practice 13 min, independent practice 9 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.

Which standard does What Borrowing Costs teach?

D2.Eco.10.3-5 — D2.Eco.10.3-5, Economics for Grade 3 to Grade 5: “Explain what interest rates are.” In plain terms, explain what an interest rate is.

What do I need to teach this lesson?

Worked figures: borrow 100, repay 105, a boatman's loan for a barge, dated 1845 and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.

What mistakes should I expect in this lesson?

Three, each a reasoning error rather than carelessness: thinks interest is a penalty for borrowing; thinks only borrowers meet interest and thinks a higher rate means a greedier lender. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.

How do I know whether the lesson worked?

The exit ticket asks: “You save 100 pounds and are paid 3 pounds a year. What is the 3 pounds, and who is paying it?.” Interest, paid by the bank for the use of your money. Calling it a gift means the price idea has not landed. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.

Is there a worksheet to go with What Borrowing Costs?

Yes — 1 printable D2.Eco.10.3-5 worksheet, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.

Is What Borrowing Costs free to use?

Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on 7 September 2026. Please do not resell it or republish it as your own.

Last reviewed 2026-09-07. Aligned to D2.Eco.10.3-5 of the C3 Framework for Social Studies State Standards.