1. Addition and Subtraction Partitioning and column addition
Objectives
Day 1
Add pairs of 2-digit numbers mentally. Add 2-digit numbers to 3-digit numbers using mental strategies.
Day 2
Add two 3-digit numbers using compact written addition.
Day 3
Add three 3-digit numbers using compact written addition.
Before teaching, be aware that:
On Day 1 it would be useful to have a set of place value cards to model partitioning; children need whiteboards and pens.
On Day 2 and Day 3 children need whiteboards and pens.
Year 4

2. Addition and Subtraction Partitioning and column addition
Starters
Day 1 Place value in 4-digit and 5-digit numbers (pre-requisite skills)
Suggested for Day 2 Count in 1/4s and 1/8s (simmering skills)
Suggested for Day 3 Addition facts to 20 (simmering skills)
Choose starters that suit your class by dragging and dropping the relevant slide or slides below to the start of the teaching for each day.
Year 4

3. Addition and Subtraction Partitioning and column addition
Starter Place value in 4-digit and 5-digit numbers
Pre-requisite skills – to use this starter, drag this slide to the start of Day 1
Ask children to use the digits 1 to 9 once to write one 4-digit number and one 5-digit number. Shuffle a set of 1 to 9 cards, then show 1 to the class. They score whatever this digit is worth in 1 of their numbers, e.g. the 5 in 15,476 scores Repeat with 3 more digits. Children find the total. Whose total was highest? Repeat.
Year 4

4. Addition and Subtraction Partitioning and column addition
Starter Count in 1/4s and 1/8s
Simmering skills – to use this starter, drag this slide to the start of Day 2
Show a 0–3 line marked in 1/4 s (see resources). Point to halfway between 0 and 1 and ask children for different ways of saying the fraction at this point. Write 1/2 below the line.
Repeat for 12/4, 22/4. Count along the line in 1/4 s: 1/4, 1/2, 3/4, 1, 11/4, 11/2 …
Show the line marked in 1/8s (see resources). Ask for equivalent fractions then count using the simplest possible fractions: 1/8, 1/4, 3/8, 1/2 …
Year 4

5. Addition and Subtraction Partitioning and column addition
Starter Addition facts to 20
Simmering skills – to use this starter, drag this slide to the start of Day 3
Children play in pairs. They each shuffle a pack of 0–10 cards and place face down. On the count of 3, they both turn over their top card. The first to say the total wins both cards. Repeat until there are no cards left. Who won most cards? Repeat.
Year 4

6. Addition and Subtraction Partitioning and column addition
Objectives
Day 1
Add pairs of 2-digit numbers mentally. Add 2-digit numbers to 3-digit numbers using mental strategies.
Year 4

7. Let’s remember how to add 2 numbers by partitioning.
Day 1: Add pairs of 2-digit numbers mentally. Add 2-digit numbers to 3-digit numbers using mental strategies.
4 0
2 0 4 8 +
Let’s remember how to add 2 numbers by partitioning.
Partition the numbers into 10s and 1s.
4 0
2 0 4 8
2 0
4 0 +
6 0 = 4 8
1 0 2
Add the 10s, then the 1s.
Then add together to find the total.
1 0 2
6 0 + =
7 0
Year 4

8. Let’s see how to add a 2-digit number to a 3-digit number.
Day 1: Add pairs of 2-digit numbers mentally. Add 2-digit numbers to 3-digit numbers using mental strategies.
Let’s try
Let’s see how to add a 2-digit number to a 3-digit number.
First partition the numbers:
178 = and 31 =
Then re-order the 10s and 1s and add: = =
= 209
It’s O.K. to do some jottings to help!
Year 4

9. Now look at these 4 questions:
Day 1: Add pairs of 2-digit numbers mentally. Add 2-digit numbers to 3-digit numbers using mental strategies.
Now look at these 4 questions:
Talk to your partner… How would you do each one?
Try with some jottings.
What do you think is the most efficient strategy for each?
e.g. For you can add 20 and subtract 1.
Today would be a great day to use a problem-solving investigation – Make 100 – as the group activity, which you can find in this unit’s IN-DEPTH INVESTIGATION box on Hamilton’s website.
Alternatively, children can now go on to do differentiated GROUP ACTIVITIES. You can find Hamilton’s group activities in this unit’s TEACHING AND GROUP ACTIVITIES download.
WT: Children roll five 1-9 dice (or use 1-9 cards) and use the numbers to create 3-digit + 2-digit questions that meet various criteria.
Year 4

10. Challenge
The Practice Sheet on this slide is suitable for most children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT: Adding two 2-digit numbers and 3-digit + 2 digit (Sheet 1)
ARE: Adding two 2-digit numbers and 3-digit + 2 digit (Sheet 1)
GD: Adding two 2-digit numbers and 3-digit + 2 digit with missing numbers (Sheet 2)
Year 4

11. Addition and Subtraction Partitioning and column addition
Objectives
Day 2
Add two 3-digit numbers using compact written addition.
Year 4

12. Try 324 + 439 on your whiteboards using the compact written method.
Day 2: Add two 3-digit numbers using compact written addition.
324
+ 439
Set the numbers out with 100s, 10s and 1s lined up. Don’t forget the space above the line for any 10s digits from adding 1s or 100s digits from the 10s.
Try on your whiteboards using the compact written method.
324
+ 439 1 3
First add the 1s.
4 + 9 = ?
Look where the digits go.
324
+ 439 1 63
Next the 10s.
= ?
Don’t forget that last 10.
324
+ 439 1
763
Finally add the 100s.
= ?
Year 4

13. Try 246 + 372 on your boards using the written method. 266 + 372
Day 2: Add two 3-digit numbers using compact written addition.
Try on your boards using the written method.
266
+ 372
Let’s check the steps. Set it out clearly.
266
+ 372 8
First add the 1s.
6 + 2 = ?
266
+ 372 1
638
Finally add the 100s.
= ?
266
+ 372 1 38
Next the 10s.
= ?
Why is there a 1 under the 300?
Children can now go on to do differentiated GROUP ACTIVITIES. You can find Hamilton’s group activities in this unit’s TEACHING AND GROUP ACTIVITIES download.
WT: Practising compact addition using place value equipment to support.
ARE: Practising compact addition.
GD: Magic square adding 3 numbers.
Year 4

14. The Practice Sheet on this slide is suitable for most children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT: Adding 3-digit numbers using compact addition (Sheet 1).
ARE: Adding 3-digit numbers using compact addition (Sheet 1).
GD: Adding 3-digit numbers using compact addition (Sheet 2).
Challenge
Year 4

15. Addition and Subtraction Partitioning and column addition
Objectives
Day 3
Add three 3-digit numbers using compact written addition.
Year 4

16. Try 592 + 235 on your whiteboards using the written method.
Day 3: Add three 3-digit numbers using compact written addition.
592
+ 235
Set the numbers out with 100s, 10s and 1s lined up. Don’t forget the space above the line for any 10s digits from adding 1s or 100s digits from the 10s.
Try on your whiteboards using the written method.
592
+ 235 7
First add the 1s.
Place the answer carefully.
592
+ 235 1 27
Next the 10s.
= ?
Don’t forget the 1 under the 100s.
592
+ 235 1
827
Finally add the 100s.
Year 4

17. Let’s try the same method to add 3 numbers!
Day 3: Add three 3-digit numbers using compact written addition.
Let’s try the same method to add 3 numbers!
Let’s check the steps.
123
474
+ 332
Add the 1s.
= ?
123
474
+ 332 9
123
474
+ 332 1
929
Lastly, the 100s.
= ?
123
474
+ 332 1 29
Next the 10s.
= ?
Don’t forget the extra 100!
Year 4

18. Where did you put the digits?
Day 3: Add three 3-digit numbers using compact written addition.
238
111
+ 216
Set it out neatly!
Now try
on your whiteboards.
238
111
+ 216 1 5
Add the 1s.
= 15
Where did you put the digits?
238
111
+ 216 1 65
Next the 10s.
= ?
238
111
+ 216 1
565
Lastly, the 100s.
= ?
Children can now go on to do differentiated GROUP ACTIVITIES. You can find Hamilton’s group activities in this unit’s TEACHING AND GROUP ACTIVITIES download.
WT: Use digit cards to generate three 3-digit numbers and compact addition to add; may using place value equipment to support expanded notation.
ARE: Use digit cards to generate three 3-digit numbers and compact addition to add.
GD: Finding sets three 3-digit numbers that necessitate different numbers of ‘carry’ moves.
Year 4

19. The Practice Sheet on this slide is suitable for most children.
Differentiated PRACTICE WORKSHEETS are available on Hamilton’s website in this unit’s PROCEDURAL FLUENCY box.
WT: Addition word problems with three 3-digit numbers (Sheet 1).
ARE: Addition word problems with three 3-digit numbers (Sheet 2).
GD: Addition word problems with three 3-digit numbers (Sheet 2).
Challenge
Year 4

20. Addition and Subtraction Partitioning and column addition
Well Done! You’ve completed this unit.
Objectives
Day 1
Add pairs of 2-digit numbers mentally. Add 2-digit numbers to 3-digit numbers using mental strategies.
Day 2
Add two 3-digit numbers using compact written addition.
Day 3
Add three 3-digit numbers using compact written addition.
You can now use the Mastery: Reasoning and Problem-Solving questions to assess children’s success across this unit. Go to the next slide.
Year 4

21. Addition and Subtraction Unit 1
Problem solving and reasoning questions   
Complete these additions mentally, with only the answer written down!
= and =
Use a different method for each one and explain both of your strategies.
Write the missing numbers in this calculation:
If 378 is subtracted from a number to leave 284, what was the number?
Add using expanded column addition.
Year 4