Short Blocks

# Maths Year 3/4 Summer Addition & Subtraction (B)

Each unit has everything you need to teach a set of related skills and concepts.

## Money: finding change and differences(suggested as 5 days)

### Planning and Activities

Day 1
Model using Frog to find change from £5, £10 and £20 when buying one or several items.
Group Activities: T with Y3
Y3 -- Practise finding change from £5, £10 and £20.
-- Choose two items that add up to under £5, £10 or £20, then calculate change.
Y4 -- Buy multiple items that add up to under £20, then calculate change.
-- Choose two items that add up to under £5, £10 or £20, then calculate change.

Day 2
Model using Frog to find change from £100 when buying several items. Represent problems with a bar model.
Group Activities: T with Y4
Y3 Use the in-depth problem-solving investigation ‘Step Change’ as today’s group activity.
Or, use these activities:
-- Practise finding change from £100 for a range of items.
-- Play ‘Change from £100 pairs’.
Y4 -- Practise finding change from £100 when buying 2 or 3 items.

Day 3
Model finding differences using Frog, e.g. a game costs £18, if I have £7.55 how much more will I need to save?
Further Teaching with Y4
Use Frog to calculate differences between two amounts: £28.84 and £32.37; £23.24 and £18.78.
Group Activities: T with Y3
Y3 -- Calculate how much more money is needed to pay for a range of items.
-- Calculate how much more money is needed to pay for a more expensive version of an item.
Y4 -- Find the difference between two amounts of money.

Day 4
Explore a range of 3-digit subtractions to discuss the choice of most appropriate/efficient strategies.
Further Teaching with Y4
Reasoning about when to use mental or written subtraction in a range of examples.
Group Activities: T with Y4
Y3 -- Subtract two 3-digit numbers, beginning to recognise when to use each of two different mental strategies.
-- Find the mystery missing numbers that have been subtracted from 3-digit numbers.
Y4 -- Justify choices for, then use, mental or written strategies for subtraction.
-- Sort calculations according to whether they are more efficiently solved mentally or using a written method.

Day 5
Discuss several word problems. Would you use addition or subtraction calculations? Discuss how a sketch, number line or bar model can support visualisation before answering.
Group Activities: T with Y3
Y4 Use the in-depth problem-solving investigation ‘Prime Addition Squares’ as today’s group activity.
Or, use these activities:
Y3/Y4 -- Solve single-step word problems in a group, then in pairs.
-- Fill the gaps with missing numbers in multi-step number stories.

### You Will Need

• Mini-whiteboards and pens
• Items that might be for sale in a seaside shop, e.g. sun cream, beach towel, bucket, spade with prices £2.74, £1.43, £8.53 and £5.72
• Toy labelled £4.67; a real £5 and £10 note
• ‘Finding change’ (see resources)
• ‘Penny lines’ (see resources)
• ‘The beach shop’ (see resources)
• Coins
• 1–6 dice
• Calculators
• ‘Finding change from £100’ (see resources)
• ‘Finding change from £20’ sheets (see resources)
• ‘Set A’ and ‘Set B’ game cards (cut up and separated into two piles for each game, see resources)
• Picture of a console/computer game
• ‘How much more?’ Sheets 1 and 2 (see resources)
• ‘0–£1 penny line’ (see resources)
• ‘Items for sale’ sheet (see resources)
• ‘Money cards’ Sets A and B’ (see resources)
• Flipchart and pens
• ‘Mental or written?’ Sheet 1 and 2 (see resources)
• Red and blue interactive whiteboard pens
• ‘Subtracting mentally’ (see resources)
• ‘Word problems’ Sheet 1 and 2 (see resources)
• Sticky notes

### Short Mental Workouts

Day 1

Day 2
Subtraction facts to 20

Day 3
Count on in steps of 10p from any amount

Day 4
Add/subtract multiples of 10 and 100 to/from 3-digit numbers

Day 5
Match digital and analogue times

### Worksheets

Day 1
Y3 Find change from £5, £10 or £20.
Y4 Find change from £5, £10 or £20.

Day 2
Y3 Find change from £20 or £100.
Y4 Find change from £50 or £100.

Day 3
Y3 How much more (comparing costs)?
Y4 Find differences (money).

Day 4
Y3 Subtract mentally.
Y4 Mental or written subtraction?

Day 5
Y3 Addition and subtraction word problems.
Y4 Addition and subtraction word problems.

### Mastery: Reasoning and Problem-Solving

Y3

• Calculate the change from £10 when buying:
Key ring £5.68
Cards £7.75
Pen £6.43
• Calculate the change from £50 when buying:
Game £34.75
Controller £42.56
Case £28.67
• Calculate the change from £100 when buying:
Game £67.43
Console £85.85
Tablet £73.68

Y4

• Write the missing numbers:
£26.67 = £100 – ☐
9381 – 5864 = ☐
1001 – ☐ = 784
• True or false? Explain your ideas:
-- Subtracting from a multiple of 1000, it is best to use Frog.
-- Subtracting a 3-digit number from a 4-digit number always gives an answer greater than 1000.
-- Subtracting 4827 from 7284 will only involve moving amounts from 1 column.
-- Subtracting 895 from 2222, column subtraction is not the ‘best’ method.

Y3 In-depth investigation: Step Change
Children find change from 2 or 3 notes. They explore patterns in the pence.

Y4 In-depth investigation: Prime Addition Squares
Children add sets of three 3-digit numbers to find patterns in a magic square based on prime numbers.

### Extra Support

Finding change from £1.

Y4: Pick ‘n’ Mix
Using place value to add and subtract to/from 3-digit numbers.