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Measure - Money: calculating totals and giving change

Grade 3IGCSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Units of Money: Understanding the relationship between pounds (£) and pence (p), where £1 = 100p.

Decimal Notation: Writing amounts of money correctly using a decimal point (e.g., £2.50 means 2 pounds and 50 pence).

Calculating Totals: Adding multiple prices together using column addition or partitioning.

Calculating Change: Finding the difference between the amount paid and the total cost using subtraction or the 'counting on' method.

Rounding and Estimation: Estimating the total cost to ensure the final calculation is reasonable.

📐Formulae

Total Cost=Price of Item 1+Price of Item 2+\text{Total Cost} = \text{Price of Item 1} + \text{Price of Item 2} + \dots

Change=Amount PaidTotal Cost\text{Change} = \text{Amount Paid} - \text{Total Cost}

£1.00=100p£1.00 = 100\text{p}

💡Examples

Problem 1:

Sarah buys a toy car for £3.40 and a ball for £1.25. How much does she spend in total?

Solution:

£4.65

Explanation:

Add the pounds and pence separately or use column addition: £3.40 + £1.25. Adding the pence: 40p + 25p = 65p. Adding the pounds: £3 + £1 = £4. Total = £4.65.

Problem 2:

Tom pays for a £7.50 book using a £10 note. How much change should he receive?

Solution:

£2.50

Explanation:

Subtract the cost from the amount paid: £10.00 - £7.50. You can 'count on' from £7.50 to £8.00 (50p) and then from £8.00 to £10.00 (£2). Combining these gives £2.50.

Problem 3:

Lily has £5.00. She wants to buy three stickers that cost 80p each. Does she have enough money?

Solution:

Yes, she will have £2.60 left.

Explanation:

First, calculate the total cost: 3 x 80p = 240p. Convert 240p to pounds: £2.40. Since £2.40 is less than £5.00, she has enough money. The change would be £5.00 - £2.40 = £2.60.