Topicme275f3e9ae5fafb5_1528449000663_0Topic

Adding natural numbers in memory

Levelme275f3e9ae5fafb5_1528449084556_0Level

Second

Core curriculumme275f3e9ae5fafb5_1528449076687_0Core curriculum

II. Calculations on natural numbers. Student:

1) adds and subtracts natural numbers, two‑digit or higher, adds a single‑digit number to any natural number and subtracts from any natural number.

Timingme275f3e9ae5fafb5_1528449068082_0Timing

45 minutes

General objectiveme275f3e9ae5fafb5_1528449523725_0General objective

Performing uncomplicated calculations in memory or in more difficult word problems and the using these skills in practical situations.

Specific objectivesme275f3e9ae5fafb5_1528449552113_0Specific objectives

1. Discovering the properties of addition.

2. Using different ways of adding two‑digit natural numbers in memory.

3. Communicating in English, developing mathematical and basic scientific and technical and IT competences, shaping learning skills.

Learning outcomesme275f3e9ae5fafb5_1528450430307_0Learning outcomes

The student:

1. Discovers the properties of addition.

2. Uses different methods of addition of two‑digit natural numbers in memory.

Methodsme275f3e9ae5fafb5_1528449534267_0Methods

1. Discussion.

2. JIGSAW.

Forms of workme275f3e9ae5fafb5_1528449514617_0Forms of work

1. Whole class.

2. Group work.

Lesson stages

Introductionme275f3e9ae5fafb5_1528450127855_0Introduction

Students recall how to add natural numbers, what the numbers and the resultresultresult of addition are called.

[Illustration 1]

Procedureme275f3e9ae5fafb5_1528446435040_0Procedure

1. Students solve equations by guessing the resultresultresult.

They record the observed property of addition in their notebooks.

a) 4 + x = 4,

b) x + 5 = 5,

c) 0 +6 = x,

d) 8 + 0 = x.

Students should draw a conclusion:me275f3e9ae5fafb5_1527752263647_0conclusion:

- If one addend is equal to zero, then the sum equals the other addend.me275f3e9ae5fafb5_1527752263647_0- If one addend is equal to zero, then the sum equals the other addend.

Students work individually using computers. They open slideshow and observe how we can add two numbers to each other.

After completing the exercise, the students present the results of their observations.

[SLIDESHOW 1]

Students should draw a conclusion:

- In the addition, the order of addends can be changed but the sumsumsum will not change, e.g. 2 + 3 = 3 + 2.

The teacher informs students that this feature of addition is called the commutative property of addition.

Students work individually using computers. They open slideshow and observe in what order we can add three numbers to each other.

After completing the exercise, the students present the results of their observations.

[SLIDESHOW 2]

Students should draw a conclusion:

- By adding several numbers, you can combine two addends freely, and the sumsumsum will not change,

e.g. (2 + 3) + 4 = 2 + (3 + 4).

The teacher informs the students that this addition feature is called associative property of addition.

The JIGSAW method.

The teacher divides the students into groups of 3 people. Each student has the same task to solve, but everyone in the group has to use a different one of the following methods of adding in memory.

After solving the task, students meet in groups that have solved the task in the same way. They discuss solutions, explain doubts.

 Then they return to the initial groups and present the method applied to the solution to other members of the group.

Task

Analyze the method of adding in memory below. Using the method presented in the drawing below, calculate the given sums.

[Illustration 2]

a) 34 + 43,

b) 46 + 56,

c) 68 + 36,

d) 79 + 56,

e) 57 + 38.

Task

Analyze the method of adding in memory below. Using the method presented in the drawing below, calculate the given sums.

[Illustration 3]

a) 34 + 43,

b) 46 + 56,

c) 68 + 36,

d) 79 + 56,

e) 57 + 38.

Task

Analyze the method of adding in memory below. Using the method presented in the drawing below, calculate the given sums.

[Illustration 4]

a) 34 + 43,

b) 46 + 56,

c) 68 + 36,

d) 79 + 56,

e) 57 + 38.

Students use acquired skills to solve tasks.

Task

Calculate.

a) 25 + 46 + 65 + 84,

b) 31 + 75 + 39 + 15,

c) 37 + 52 + 13 + 18.

Task

Julia collected 27 stickers, and Basia 36. How many stickers do girls have together?

An extra task
Calculate by any method:
a) 120 + 356,
b) 254 + 657.
me275f3e9ae5fafb5_1527752256679_0An extra task
Calculate by any method:
a) 120 + 356,
b) 254 + 657.

Lesson summaryme275f3e9ae5fafb5_1528450119332_0Lesson summary

Students do revision exercises.

Then they summarize the lesson together, formulating rules to remember:

- Adding numbers and the resultresultresult of adding are called sumsumsum, and the numbers that we add are addends.

- If one of the addends is equal to zero, then the sumsumsum equals the other addendaddendaddend.

- In addition, you can change the order of addends, and the sumsumsum will not change, e.g. 2 + 3 = 3 + 2. We call it Commutative property of addition

- By adding a few numbers, you can combine the addends and the totaltotaltotal will not change,

e.g. (2 + 3) + 4 = 2 + (3 + 4). We call it associative property of addition.

Selected words and expressions used in the lesson plan

addendaddendaddend

commutative additioncommutative additioncommutative addition

resultresultresult

sumsumsum

totaltotaltotal

me275f3e9ae5fafb5_1527752263647_0
me275f3e9ae5fafb5_1527752256679_0
me275f3e9ae5fafb5_1527712094602_0
me275f3e9ae5fafb5_1528449000663_0
me275f3e9ae5fafb5_1528449084556_0
me275f3e9ae5fafb5_1528449076687_0
me275f3e9ae5fafb5_1528449068082_0
me275f3e9ae5fafb5_1528449523725_0
me275f3e9ae5fafb5_1528449552113_0
me275f3e9ae5fafb5_1528450430307_0
me275f3e9ae5fafb5_1528449534267_0
me275f3e9ae5fafb5_1528449514617_0
me275f3e9ae5fafb5_1528450135461_0
me275f3e9ae5fafb5_1528450127855_0
me275f3e9ae5fafb5_1528446435040_0
me275f3e9ae5fafb5_1528450119332_0
result1
result

wynik dodawania

R1N96SqlVU8Mk1
wymowa w języku angielskim: result
sum1
sum

suma

Rw8c3tkAEzgNG1
wymowa w języku angielskim: sum
addend1
addend

Składnik dodawania

RGjL2nm3qCFAM1
wymowa w języku angielskim: addend
total1
total

wynik dodawania

RKWrTWTs96FUP1
wymowa w języku angielskim: total
commutative addition1
commutative addition

przemienność dodawania

RMRUhEKzjM9Cw1
wymowa w języku angielskim: commutative addition