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# Maths Year 2 Autumn Addition and Subtraction

Each unit has everything you need to teach a set of related skills and concepts. 'Teaching for Understanding' provides whole-class teaching and fully differentiated adult-led group activities. ‘Problem-solving and Reasoning’ develops these skills, and includes questions to enable you to assess mastery. Practice sheets ensure procedural fluency. Extra support activities enable targeted work with children who are well below ARE.

‘UNIT PLAN’ gives you a text version of all parts of the unit to use in your school planning documentation. ‘DOWNLOAD ALL FILES’ gives you that unit plan plus all of associated documents. These bulk downloads are available to friends and School Subscribers. These bulk downloads are added value for Hamilton Friends and School Subscribers.

## Unit 1 Addition/subtraction facts; missing nos (suggested as 3 days)

### Objectives

Know addition and subtraction facts
Missing numbers

Unit 1: ID# 2153

National Curriculum
Add/Sub (i) (ii) (v)

Hamilton Objectives
7. Know securely number pairs for all the numbers up to and including 20.
14. Recognise that addition and subtraction are inverse operations; use addition to check subtractions and solve missing number problems.

### Teaching and Group Activities for Understanding

Day 1 Teaching
Show a number balance with weights: 6 one side and 10 on the other. If you hang a weight on LHS it’ll balance. Balance 6 and 4 with 10. Record 6 + □ = 10. Discuss how 4 goes in the box. Repeat for other bonds to 10. Then for 9, 8 and 7.
Group Activities
Use the ‘Addition Towers’ in-depth problem-solving investigation below as today’s group activity.
Or, use these activities:
-- Children use balance bars to create balanced number sentences up to 10.

Day 2 Teaching
Show a bead frame (2 rows of 10 beads) or a bead string (20 beads). Hide a number of beads and ask children to say missing number. Record with a missing number sentence: 15 + [_] = 20. Repeat for other bonds to 20.
Group Activities
-- Children find missing numbers to create a pair of numbers that add up to 20.

Day 3 Teaching
Show picture of a strip of 10 red cubes with a strip of 6 blue and 4 yellow cubes below (see resources) or use real interconnecting cubes. Demonstrate pairs to 10 and 20. Write related addition and subtraction facts.
Group Activities
-- Children use bar models to create pairs of numbers that add up to 10 and 20, using inverse operations.

### You Will Need

• 1-100 grid (see resources)
• Ten 2-digit number cards
• Number balance, or number balance from nrich.org
• 1-10 number cards
• 20 bead frame, 20 bead strings
• Five ‘Slidy box’ cards
• Additional activity sheets (see resources)
• Interconnecting cubes, e.g. multilink

### Mental/Oral Maths Starters

Day 1
Pairs to 10 (pre-requisite skills)

Suggested for Day 2
Say one more or one less than any 2-digit number (simmering skills)

Suggested for Day 3
Place value in 2-digit numbers (simmering skills)

### Procedural Fluency

Day 1
Children explore the different ways to find a total of 10 using 2 or 3 numbers.

Day 2
Children find the missing numbers for totals of 10 and 20.

Day 3
Children explore possible solutions to find a total of 20.

### Mastery: Reasoning and Problem-Solving

• Write the pairs of possible missing numbers.
 20 11
• How many different ways are there of writing numbers in the 2 boxes in this sentence?
☐ + ◯ = 10
What about if the 2 boxes = 9? Or = 8?
• You have 21 cards - 0 to 20. You can create how many pairs of numbers making 20? Write these. Write the pair you cannot create.
• Cuisenaire counting’ activity from nrich.org

In-depth Investigation: Addition Towers
Children find the total number of spots on 2 dice in a game context, and consider why some totals come up more frequently than others.

### Extra Support

10 Totally Rocks
Finding pairs with a total of 10

## Unit 2 Know how many to next multiple of 10 (suggested as 3 days)

### Objectives

How many to next multiple of 10
Unit 2: ID# 2161

National Curriculum
Add/Sub (i) (ii) (iii)

Hamilton Objectives
12. Begin to count up to find a difference between 2 numbers with a small gap.
8. Know different unit patterns when adding or subtracting, first when not crossing a 10 in numbers up to 100.
6. Use place value and number facts to solve problems, e.g. 60 - ☐ = 20.

### Teaching and Group Activities for Understanding

Day 1 Teaching
Show 7 beads on 100 bead bar. How many more to make 10? Show 17 beads. How many more to 20? Show pair to 10: 7 & 3. Show 27 beads. What is next multiple of 10 after 27? How many to 30? Look at pair to 10? Repeat with 37, 47, 57…97. Record matching number sentences.
Group Activities
-- Children roll a dice to create a 2-digit number. They then use a bead string to see what needs to be added to make the next multiple of 10.

Day 2 Teaching
Show 1-100 grid. Ring 36. What’s the next Wolf number? 36 + what = 40? Use grid to demonstrate counting on from 36 to 40. Repeat for 46, 76 & 86.
Group Activities
-- Children choose a number from the 1-100 grid. They need to work out what needs to be added to reach the next Wolf number.

Day 3 Teaching
Ring 68 on 1-100 grid. What’s next Wolf number? (70). Find 68 on bead bar and count on to 70. Draw hop from 68 to 70 on beaded line on board. Record 68 + 2 = 70. Repeat for other 2-digit numbers and bonds to next 10.
Group Activities
Use the ‘Sackful of 10s’ in-depth problem-solving investigation below as today’s group activity.
Or, use these activities:
-- Children get the opportunity to choose between using a number grid or beaded line to help them to solve problems that involve getting to the next multiple of 10.

### You Will Need

• 100 bead bar and cloth
• 100 bead strings
• 1-100 grid (see resources)
• A large 0-100 beaded line
• A large landmarked line (0-100, with 10s marked)
• ‘Slidy box’ cards
• Additional activity sheets (see resources)
• Post-it notes

### Mental/Oral Maths Starters

Day 1
Pairs to 10 (pre-requisite skills)

Day 2
Multiples of 10 (pre-requisite skills)

Day 2
Next multiple of 10 (pre-requisite skills)

### Procedural Fluency

Day 1
Practise finding how many to the next multiple of 10.

Day 2
Find the missing numbers in any position in an addition number sentence.

Day 3
Write number sentences to show how to calculate how many more to reach the next multiple of 10.

### Mastery: Reasoning and Problem-Solving

• Fill in the missing numbers:
65 + __ = 70
54 + __ = 60
37 + __= 40
80 – __= 71
• Write the missing number in each bar diagram:
Diagram 1
 80 6

Diagram 2

 30 26

Diagram 3

 100 85
• Mystery Number
I have 1 digit. I make 40 when added to a 2-digit number whose digits add to 9. What number am I?

In-depth Investigation: Sackful of 10s
Children play a game which requires that they add multiples of 10 using their knowledge of number bonds. They then challenge themselves to work out the longest game possible.

### Extra Support

Shape Sums
Revising pairs to 10; using pairs to 10 to find pairs to 20

What's the Gap?
Saying the next 10s number; finding how many to the next 10s number, e.g. 36 + ? = 40

## Unit 3 Add and subtract 10/20; extend to 11/21 (suggested as 4 days)

### Objectives

Add/subtract 10/20 then 11/21
Unit 3: ID# 2179

National Curriculum
Add/Sub (i) (iii) (v)

Hamilton Objectives
10. Add a 2-digit no. and 10s.
11. Count back in 1s or 10s or use number facts to take away.
14. Recognise that addition and subtraction are inverse operations; use addition to check subtractions and solve missing number problems.

### Teaching and Group Activities for Understanding

Day 1 Teaching
Show children how Spider counts in 10s down a 1-100 grid, starting anywhere on the top row. Chant in unison: 3, 13, 23, etc. Repeat. Show Spider counts down in 10s by moving back up. Count in unison. Demonstrate adding 10 by moving spider down 1 space. Record: 46 + 10 = 56. Repeat for subtracting 10. Stress that Spider doesn’t have to count in 1s!
Group Activities
-- Children make 2-digit numbers and identify 10 more and 10 less on a 1-100 grid.
Day 2 Teaching
Put 7p in a tin. Drop in a 10p coin. How much in the tin now? Repeat, dropping in 10p coins until 97p is in the tin, as children count on in 10s. Take out 10p coins one at a time, until you only have 7p left. Add/subtract 10 using coins.
Group Activities
-- Children make 2-digit prices less than 90p, adding and subtracting 10p.

Day 3 Teaching
Use Spider on a 1-100 grid. Remind children of counting up in 10s & adding 10. Model adding 11 by moving 1 space down and 1 along, Children show on their 1-100 bead strings – add 10 and add 1 more. Repeat for 20/21.
Group Activities
Use the in-depth problem-solving investigation ‘That Number Square!’ from NRICH as today’s group activity.
Or, use these activities:
-- Children work in pairs to add 10 and 11, then 20 and 21 to numbers between 20 and 70.

Day 4 Teaching
Place Spider on 51 on 1-100 grid. Children show you 51 on their bead strings, then show the number 10 less. Children subtract another 10. Record matching sentences.
Group Activities
-- Children work in pairs to subtract 10 and 11, then 20 and 21 from numbers between 40 and 100.

### You Will Need

• 1-100 demonstration grid
• Plastic spider
• 0 to 9 dice
• 1-100 grids for children (see resources).
• Place value cards
• A tin, 5p, 2p and nine 10p coins
• 5 items with prices < 90p & 5 priced > 10p
• ‘Slidy box’ cards
• Selection of coins including 10p & 1p coins
• Bead strings for children
• Large 100 beaded line
• ‘Slidy box’ cards with +/- sentences
• +10, -10 cards

### Mental/Oral Maths Starters

Day 1
Count in 10s from a single-digit number (pre-requisite skills)

Day 2
Count on and back in 10s (pre-requisite skills)

Day 3
Add/subtract 10 (pre-requisite skills)

Day 4
Count on and back in 10s (pre-requisite skills)

### Procedural Fluency

Day 1
Children complete the missing squares from a 100 grid to add and subtract 10 from a given number.

Day 2
The clothes shop. Children make clothes 10p more expensive and 10p cheaper.

Day 3
Children use bead strings or a 1-100 grid to add 10, 11, 20 and 21.
Day 4
Children use bead strings or 1-100 grid to subtract 10, 11, 20 and 21.

### Mastery: Reasoning and Problem-Solving

• What number adds to 63 to make 83? What number is subtracted from 83 to give 73?
• Write the missing numbers in the sequences:
13, __, 53, __, 93, 113
76, 56, __, __
42, __, 64, 75, __, __
• Complete this grid:
+ 31 ?
37 ? 49
82 ? 94
• Write the missing numbers:
32 + ☐ = 43
57 + ☐ = 78
76 –☐ = 54
☐ – 12 = 47
• How many times can 21 be subtracted from 100 before you get a number smaller than 21?

In-depth Investigation: That Number Square!
Explore 'smart' strategies to put numbers back in the correct place on the 100-grid. That Number Square! from nrich.maths.org.

### Extra Support

Spider's Workout
Adding and subtracting 10 using a 1-100 grid

Easy Come, Easy Go
Adding and subtracting 10 using coins

## Unit 4 Use facts to add several numbers (suggested as 2 days)

### Objectives

Use facts to add several numbers
Unit 4: ID# 2203

National Curriculum
Add/Sub (ii) (v)

Hamilton Objectives
7. Know securely number pairs for all the numbers up to and including 20, e.g. pairs which make 15 (7+8, 6+9, 5+10, 4+11, 3+12, 2+13, 1+14, 0+15).
9. Add 2 or 2 single-digit numbers, using number facts and counting up.
14. Recognise that addition and subtraction are inverse operations; use addition to check subtractions and solve missing number problems.

### Teaching and Group Activities for Understanding

Day 1 Teaching
Use a 20 bead frame to rehearse bonds to 10 and 20. Then use these facts to spot pairs to 10 and 20 when adding three numbers, e.g. 13 + 8 + 7 or 6 + 7 + 4. Encourage children to spot the bond to make the addition easy.
Group Activities
Use the in-depth problem-solving investigation ‘Getting the Balance’ from NRICH as today’s group activity. Or, use these activities:
-- Children work in pairs to use number facts in adding three or four numbers less than 20.
Day 2 Teaching
Write ■ + ▲ = 10 on f/chart. There are 2 mystery numbers here. What could they be? If square is 8, ask what triangle is? What if square was 1? So there are lots of possible answers. Repeat for different pairs of mystery numbers including subtraction: 20 - ■ - ▲ = 15.
Group Activities
-- Children learn how to find the mystery number in a number sentence using known number facts.

### You Will Need

• Bean bag
• 20 bead frame (2 rows of 10 beads with whiteboard)
• 0-20 cards
• ‘Slidy box’ cards
• 20 bead strings
• Activity sheet of mystery number sentences (see resources)

### Mental/Oral Maths Starters

Day 1
Pairs to 10 (pre-requisite skills)

Suggested for Day 2
Adding 3 numbers (simmering skills)

### Procedural Fluency

Day 1
Children complete a number search to find number bonds to 20.

Day 2
Children complete a number search to find 3 numbers that add up to 20.

### Mastery: Reasoning and Problem-Solving

• Complete these bar diagrams:
Diagram 1
 20 13

Diagram 2

 20 4
• Write a sentence with a missing number. It must also include the number 20.
• Correct Tina’s work. What mistake is she making?
13 + 17 = 20
20 – 14 = 16
20 – 11 = 19

In-depth Investigation: Getting the Balance
Can you hang weights in the right place to make the scale balance? Getting the Balance from nrich.maths.org.

### Extra Support

Give me 5...or 6 or 7
Finding pairs with a total of 5, 6 and 7

## Unit 5 Add/subtract numbers bridging 10 (suggested as 3 days)

### Objectives

Add/subtract numbers bridging 10
Unit 5: ID# 2213

National Curriculum
Add/Sub (ii) (iii) (v)

Hamilton Objectives
7. Know securely number pairs for all the numbers up to and including 20.
8. Know different unit patterns when adding or subtracting, first when not crossing a 10 and then when crossing a 10, in numbers up to 100.
11. Count back in 1s or use number facts to take away, e.g. 27-3, 52 – 4.
15. Solve problems involving addition and subtraction of numbers, using recall of number facts and appropriate models and images.

### Teaching and Group Activities for Understanding

Day 1 Teaching
Show 5 beads & 3 more on 1-100 bead bar. We all know 5 add 3! Show 15 & 3 more. Point at 5 + 3 beads in one colour. Repeat for 25 + 3, 35 + 3… 95 + 3. These are really easy - we don’t need to count on. Model on beaded line and landmarked line. Repeat for 9 – 4, 19 – 4, 29 – 4, 99 – 4.
Group Activities
-- Children use known number facts to solve addition and subtraction problems.
Day 2 Teaching
Add a single digit to a 2-digit number by bridging multiples of ten using a bead bar. Show 28 and model adding 5 beads. Once we know 8 + 5 is 13, it’s easy. 18 + 5= 23, 28 + 5 = 33, 38 + 5 = 43, etc. Repeat for other additions using beaded and landmarked lines.
Group Activities
Use the in-depth problem-solving investigation ‘Secret Number’ from NRICH as today’s group activity.
Or, use these activities:
-- Children use a landmarked or beaded line to solve addition problems using known facts.

Day 3 Teaching
Subtract a single digit from a 2-digit number by bridging multiples of 10 using a bead bar. Start with 20-2, 30-2 etc. Then show 34 – 5, 44 – 5 etc. using beaded and landmarked lines. Repeat for other subtractions.
Group Activities
-- Children use a landmarked or beaded line to solve subtraction problems using known facts.

### You Will Need

• 100 bead bar
• Bead strings
• Flip chart
• 0-100 beaded line
• 0-100 landmarked line

### Mental/Oral Maths Starters

Suggested for Day 1
Pairs to 20 (simmering skills)

Day 2
Complements to multiples of 10 (pre-requisite skills)

Day 3
Subtraction facts for 10 (pre-requisite skills)

### Procedural Fluency

Day 1
Children complete additions and subtractions that follow a pattern, encouraging them to use known number facts.

Day 2
Children rehearse adding a single-digit to a 2-digit number.

Day 3
Children practise subtracting a single-digit from a multiple of 10 and 2-digit numbers.

### Mastery: Reasoning and Problem-Solving

• Write three additions which include a 2-digit number ending in 5, and the number 7.
• Complete each sentence by writing the missing numbers.
43 + ☐ = 48
36 + 6 = ☐
☐ – 4 = 60
27 + 7 = ☐
☐ – 3 = 72
• Tom has 66 cards. He needs to get 72 to complete his set. How many more does he need?
• Complete this grid.
 + 7 45 50 68 73

In-depth Investigation: Secret Number
Annie and Ben are playing a game with a calculator. What was Annie's secret number? Adapt numbers used to ensure addition by bridging. Secret Number from nrich.maths.org.

### Extra Support

Sum Patterns
Using pattern and number bonds to work out related additions, e.g. 3 + 2 = 5, so 13 + 2 = 15, 23 + 2 = 25, 33 + 2 = 35...