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Adding using vertical algorithm (regrouping)

Maths- Part-Whole & Addition and Subtraction

Miss Thomson

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Learning objectives
Activate prior knowledge
Keywords
Adding using 2-digit numbers without regrouping
Check before independent
Adding 2-digit numbers with regrouping
Check before independent
Lesson review

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Learning objectives

I can

I can add numbers within 100 using a vertical written algorithm with regrouping

Success criteria

We will

Add 2-digit numbers using an algorithm without regrouping
Add 2-digit numbers using an algorithm with regrouping

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Key principles

The “I do” phase involves the explanation - indicates where a teacher would be explaining a concept.
Moving from “I do” to “We do” involves modelling - indicates that the teacher is demonstrating a skill or modelling a process.
Check for Understanding - Questions posed to check whether students have understood and to inform next steps.
“You do” - Practice - indicates places where students will attempt questions independently.

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We do

I do

Check for

understanding

You do

I

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CfU

W

Y

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5

Whiteboard response

All students respond to the teacher’s question, showing their responses at the same time.

Non-volunteers

The teacher asks a question, gives wait time, then calls on individual students to respond.

Independent work

Students respond to a prompt in their exercise book or booklet.

Pair share

Students discuss with the person next to them.

Choral response

Students respond orally all together.

Thumbs up, thumbs down

Students indicate whether they agree or disagree with a statement, or whether something is an example or non-example.

Engagement icons - to go in top right corner

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Curriculum Links

Objectives

I can add numbers within 100 using a vertical written algorithm with regrouping

Curriculum Codes

NSW

MA1-CSQ-01 - uses number bonds and the relationship between addition and subtraction to solve problems involving partitioning

MA2-AR-01 - selects and uses mental and written strategies for addition and subtraction involving 2- and 3-digit numbers

AC v9

AC9M2N04 - add and subtract one- and two-digit numbers, representing problems using number sentences and solve using part-part-whole reasoning and a variety of calculation strategies

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In this lesson, you will need:

Pencil

Exercise book or paper

Mini whiteboard and texta

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Image credit: FreeSVG and Pixabay

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Keywords

Add: To find the total of two or more numbers or amounts.

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Non-example

_____________________________________

+ =

7 + 1 = 5
14 - 2 = 12

Example

____________________________________

+ =

6 + 3 = 9
14 = 6 + 8

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Keywords

Regroup: To make groups of ten, or break groups of ten.

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Example

____________________________________

Non-example

____________________________________

1 ten 10 ones

10 ones 1 ten

1 ten 14 ones

20 ones 1 ten

=

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10

Review

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Regrouping base ten blocks

You can regroup base ten blocks when adding.

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I

	T	O

+

6

7

13

3

2

6

36 + 27 =

63

+1

3

We regroup when the ones are more than 9.

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Adding 2-digit numbers with regrouping

12

	T	O

+

I

4

8

12

4

2

7

44 + 28 =

72

+1

2

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Adding 2-digit numbers with regrouping

13

	T	O

+

W

6

8

14

5

3

9

56 + 38 =

94

+1

4

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Adding 2-digit numbers with regrouping

14

	T	O

+

Y

6

5

11

3

2

6

36 + 25 =

61

+1

1

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15

Adding using 2-digit numbers without regrouping

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Adding with an algorithm

You can add using an algorithm.

16

	T	O

+

I

3

2

4

23 + 23 =

46

6

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Adding 2-digit numbers using an algorithm

17

	T	O

+

6

I

4

2

1

7

8

14 + 72 =

86

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True or false: we always start adding from the ones place

True

False

True! We always start adding from the ones place.

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CfU

Image credit: Pixabay

2

4

2

4

8

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Adding 2-digit numbers using an algorithm

19

	T	O

+

7

W

6

1

6

2

8

66 + 21 =

87

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Which option has the correct answer

Option 1

Option 2

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CfU

Image credit: Pixabay

	T	O
	2	5
+	3	3
	5	8

	T	O
	2	5
+	3	3
	5	5

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Adding 2-digit numbers using an algorithm

21

	T	O

+

5

W

3

2

5

4

9

53 + 42 =

95

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Which option has the correct answer

Option 1

Option 2

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CfU

Image credit: Pixabay

	T	O
	8	6
+	1	2
	9	8

	T	O
	8	6
+	1	2
	7	7

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Independent practice

23

Y

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Adding using 2-digit numbers with regrouping

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Adding with an algorithm (regrouping)

You can regroup using an algorithm when adding.

25

	T	O

+

I

6

7

13

3

2

6

36 + 27 =

63

+1

3

We regroup when the value of the digits in the ones place equals more than 9.

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Adding 2-digit numbers with an algorithm

26

	T	O

+

2

I

4

8

12

6

2

9

64 + 28 =

92

+1

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True or false: we can have more than 1 digit in each place value column

True

False

False! We must only have one digit in each place value column.

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CfU

Image credit: Pixabay

6

4

2

8

12

6

+1

4

2

8

2

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Adding 2-digit numbers with an algorithm

28

	T	O

+

1

W

2

9

11

7

1

9

72 + 19 =

91

+1

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Which option has been regrouped?

Option 2

Option 1

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2

4

6

8

1

+1

6

4

7

6

3

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Adding 2-digit numbers with an algorithm

30

	T	O

+

5

W

6

9

15

4

2

7

46 + 29 =

75

+1

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Which option has NOT been regrouped?

Option 2

Option 1

31

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4

3

4

2

8

5

+1

5

7

2

9

8

6

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Independent practice

32

Y

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Lesson review

We have been learning about:

Part-whole addition

Using

An algorithm

Adding 2-digit numbers with regrouping

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CfU

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Teacher guidance - Adding 2-digit numbers using an algorithm without regrouping

Key teaching points:

Adding 2-digit numbers using an algorithm without regrouping

Key questions:

What place value column do we start in?

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Teacher guidance - Adding 2-digit numbers using an algorithm with regrouping

Key teaching points:

Adding 2-digit numbers using an algorithm with regrouping

Key questions:

When do we need to regroup?
Can we have more than 9 ones in the ones place?

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