Skip to content
Cambridge IGCSE0607

Money

International Mathematics 0607 Chapter Notes

What this chapter covers

Money
ShareWhatsAppPost
Money notes

Read online free. Download a watermarked copy with a free account.

Read the notes

The full Money notes as text: skim, search, and jump between subtopics.

~7 min read

In this chapter

  1. 1Bills, totals and change
  2. 2Dollars and cents
  3. 3The greatest number you can buy
  4. 4Working backwards from a total
  5. 5Changing one currency into another
  6. 6Spend abroad, then change back

1. Bills, totals and change

To calculate with money, find the cost of each item first: price each × number bought. Add the costs to get the total.

The change is what is left from the amount paid. Do not stop at the total cost. Take it away from the amount paid.

cost = price each × number bought

change = amount paid - total cost

Examiner insight

“A few candidates worked out the cost for the 7 cans and then forgot to subtract their answer from $5 to find the change.” “For actual money calculations of this type, it is not appropriate to round at all.”

Worked example 15 marks

Tanya goes shopping.

(a) Complete the shopping bill.

(b) Calculate the change Tanya receives from 20 dollars.

itemcost ($)
2 kg of tomatoes at 2.40 dollars for each kg
4 peppers at 90 cents each
3 kg of onions at ........ for each kg4.50
Total
  1. 1

    Tomatoes: 2 × 2.40 = 4.80 dollars [1]

  2. 2

    Peppers: 90 cents = 0.90, so 4 × 0.90 = 3.60 [1]

  3. 3

    Onions, price for each kg: 4.50 ÷ 3 = 1.50 [1]

  4. 4

    Total: 4.80 + 3.60 + 4.50 = 12.90 [1]

  5. 5

    (b) Change: 20 - 12.90 = 7.10 dollars [1]

2. Dollars and cents

Write every price in one unit before you add. Either change cents to dollars (divide by 100) or work wholly in cents and change at the end.

When a charge changes after a set amount, work out each part at its own rate, then add the parts. Give the answer in the unit the question asks for.

40 cents = $0.40

$1 = 100 cents

Examiner insight

“Occasionally there was some confusion between dollars and cents.” “A few candidates went on and changed their answer into dollars.”

Worked example 13 marks

Gina uses 866 units of electricity. For the first 140 units, Gina pays 23 cents for each unit. For the remaining units, she pays 19.5 cents for each unit.

Work out how much Gina pays for these 866 units of electricity. Give your answer in dollars ($).

  1. 1

    First 140 units: 140 × 23 = 3220 cents [1]

  2. 2

    Remaining units: 866 - 140 = 726, so 726 × 19.5 = 14 157 cents [1]

  3. 3

    Total: 3220 + 14 157 = 17 377 cents = 173.77 dollars [1]

3. The greatest number you can buy

To find how many items a sum of money buys, divide the money by the price of one item.

The answer must be a whole number of items. Look at the decimal and round down. You cannot buy part of a book, and the next whole book costs more than you have.

number bought = money available ÷ price of one item

Examiner insight

“Some candidates rounded their answer up rather than down.” “A few candidates divided by 5 rather than multiplying by 5.”

Worked example 13 marks

A book costs 6.72 dollars.

(a) Work out the cost of 5 of these books.

(b) Work out the greatest number of these books that can be bought with 100 dollars.

  1. 1

    (a) 5 × 6.72 = 33.60 dollars [1]

  2. 2

    (b) 100 ÷ 6.72 = 14.88… [1]

  3. 3

    Round down: the greatest number is 14 [1]

4. Working backwards from a total

Sometimes the total is given and you must find the number of items. Take away any fixed amount first. Then divide what is left by the price of each item.

Write a label beside each line, such as "total for the day rate". The method has many stages, so clear working lets you check each one.

number of items = (total - fixed amount)/(price of each item)

Examiner insight

“There are many stages to the method so candidates must set out their work clearly so they can check they have performed the calculation correctly.”

Worked example 12 marks

Ryan is paid 12 dollars each day to pick asparagus. The asparagus Ryan picks is weighed. Ryan is also paid 1.50 dollars for each kilogram of asparagus he picks.

(c) Ryan works for 5 days and is paid a total of 189 dollars.

Work out how many kilograms of asparagus Ryan picks in these 5 days.

  1. 1

    Pay for 5 days: 5 × 12 = 60. Pay for the asparagus: 189 - 60 = 129 [1]

  2. 2

    Kilograms: 129 ÷ 1.50 = 86 kg [1]

5. Changing one currency into another

An exchange rate says how much of one currency equals one unit of another, such as 1 dollar = 18 rand.

With this rate, each dollar becomes 18 rand. To change dollars into rand, multiply by the rate. To change rand back into dollars, divide by the rate. Check the direction: here the number of rand must be bigger than the number of dollars.

other currency = dollars × rate

dollars = other currency ÷ rate

Examiner insight

“Most candidates were able to correctly convert their answer back into dollars.”

Worked example 14 marks

Do not use a calculator.

The exchange rate is 1 dollar = 18 rand.

(a) Change 120 dollars into rand.

(b) Change 450 rand into dollars.

  1. 1

    (a) Dollars to rand: multiply by the rate [1]

  2. 2

    120 × 18 = 2160 rand [1]

  3. 3

    (b) Rand to dollars: divide by the rate [1]

  4. 4

    450 ÷ 18 = 25 dollars [1]

6. Spend abroad, then change back

Some questions need two conversions. Change into the foreign currency, do the money calculation in that currency, then change the remainder back.

Do not round in the middle of the method. Round only the final answer, to the nearest cent when the question asks for it.

remainder = amount changed - amount spent

Worked example 14 marks

The exchange rate is 1 dollar = 0.92 euros.

Mia changes 500 dollars into euros. She spends 346.50 euros. She changes the rest back into dollars.

Work out how many dollars she receives. Give your answer to the nearest cent.

  1. 1

    Euros received: 500 × 0.92 = 460 [1]

  2. 2

    Euros left: 460 - 346.50 = 113.50 [1]

  3. 3

    Back to dollars: 113.50 ÷ 0.92 = 123.369… [1]

  4. 4

    123.37 dollars, to the nearest cent [1]

Recap

  • Cost = price each × number bought. Total = sum of the costs.
  • Change = amount paid − total cost.
  • Use one unit, dollars or cents, in a whole calculation.
  • Greatest number you can buy: divide, then round down.
  • Given the total: take away the fixed amount first, then divide by the price of each item.
  • Exchange rate 1 dollar = 18 rand: multiply by 18 to change dollars into rand, divide by 18 to change back.
  • Do not round in the middle of a money calculation. Round only at the end, and only if the answer is not exact.

End-of-chapter exercise

Test yourself on the whole chapter. Work through these before moving on.

  1. Do not use a calculator. Pens cost 1.20 dollars each. Work out the cost of 5 pens.1 mark
  2. Do not use a calculator. Sam buys 3 notebooks at 2.35 dollars each. He pays with a 10 dollar note. Work out his change.2 marks
  3. Do not use a calculator. Stickers cost 60 cents each. Work out the cost of 4 stickers. Give your answer in dollars.2 marks
  4. Do not use a calculator. Maya buys 2 coffees at 2.80 dollars each and 3 cakes at 95 cents each. She pays with 10 dollars. Work out her change.4 marks
  5. Concert tickets cost 7.35 dollars each. Work out the greatest number of tickets that can be bought with 50 dollars.2 marks
  6. Do not use a calculator. For the first 100 units of water, a customer pays 20 cents for each unit. For the remaining units, the customer pays 15 cents for each unit. A customer uses 300 units. Work out how much the customer pays. Give your answer in dollars.3 marks
  7. Do not use a calculator. The exchange rate is 1 dollar = 80 rupees. Change 2400 rupees into dollars.2 marks
  8. The exchange rate is £1 = 1.18 euros. A jacket costs £80 in one shop and 95 euros in another shop. Work out how much cheaper the cheaper jacket is. Give your answer in euros.3 marks
  9. The exchange rate is 1 dollar = 0.92 euros. Noor changes 200 dollars into euros. Museum tickets cost 13.50 euros each. She buys the greatest number of tickets she can. She then changes the euros she has left back into dollars. Work out how many dollars she receives. Give your answer to the nearest cent.5 marks
  10. A phone company in South Africa charges in rand, where 1 rand = 100 cents. Calls cost 1.20 rand for each minute for the first 50 minutes in a month. Each minute after that costs 85 cents. The exchange rate is 1 dollar = 17.5 rand. Thandi's calls for one month cost the same as 11.20 dollars. Work out the total number of minutes of calls Thandi makes that month.5 marks

Free notes are just the start.

Unlock every Workbook and Chapter at a Glance, and generate your own worksheets and predicted papers.

Explore plans

Related chapters

Types of numberSetsPowers and rootsFractions, decimals and percentagesOrderingThe four operations