Topicm3e82128db3545669_1528449000663_0Topic

Subtraction of the integerssubtraction of the integersSubtraction of the integers

Levelm3e82128db3545669_1528449084556_0Level

Second

Core curriculumm3e82128db3545669_1528449076687_0Core curriculum

III. The integers.

The student:

1) interprets the integers on a number line,

2) does simple mental calculations of integers.

Timingm3e82128db3545669_1528449068082_0Timing

45 minutes

General objectivem3e82128db3545669_1528449523725_0General objective

I. Accounting ability.

1. Doing the simple operations of mental calculation or more difficult ones in writing and using these abilities in practical situations.

Specific objectivesm3e82128db3545669_1528449552113_0Specific objectives

1) Subtraction of the integerssubtraction of the integersSubtraction of the integers.

2) Solving the text task using the subtraction of the integerssubtraction of the integerssubtraction of the integers.

3) Communicating in English; developing mathematical and basic scientific, technical and digital competences; developing learning skills.

Learning outcomesm3e82128db3545669_1528450430307_0Learning outcomes

The student:

- subtracts the integers, interprets the integers on the number line,

- specifies the sign of the integers.

Methodsm3e82128db3545669_1528449534267_0Methods

1) Learning game.

2) Situational analysis.

Forms of workm3e82128db3545669_1528449514617_0Forms of work

1) Individual work.

2) Work in pairs.

3) Group work.

Lesson stages

Introductionm3e82128db3545669_1528450127855_0Introduction

The student prepares the cards and bring them to the class. There is one of the following numbers on each card: -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

The teacher introduces the topic of the lesson: subtracting the integers.

Revision of the definition and the properties of the opposite numbers.

Procedurem3e82128db3545669_1528446435040_0Procedure

The students work individually using their computers. They are going to watch the method of subtracting the integers and draw a conclusion.

[Slideshow]

They should draw a conclusion:
To subtract the positive number from the integer on the number line we move in opposite direction of the number line(to the left).
To subtract the negative number from the integer on the number line we move in the direction of the number line (to the right).m3e82128db3545669_1527752263647_0To subtract the positive number from the integer on the number line we move in opposite direction of the number line(to the left).
To subtract the negative number from the integer on the number line we move in the direction of the number line (to the right).

The students work in pairs. They use the cards they have prepared at home.

Each of the players chooses one card and draws the number line.Next, he indicates the number on it. He substracts theopponent’s number from the number he has chosen. The winner is the person who scores the higher result. The students repeat the activity for few times. They check their results by using the calculators.

Task
The students discuss how to find out the result of subtraction when the negative integerintegerinteger is a subtrahend.They analyse the examples given by theteacher.

9 – (- 3) = 9 + 3 = 12

(- 10) – (- 4) = (- 10) + 4 = (- 6)

(- 7) – 3 = (- 7) + (- 3) = (- 10)

12 – 30 = 12 + (- 30) = (- 18)

The students should draw thefollowing  conclusion:
The difference of two integers equals the sum of the first number and the opposite number of the second one.m3e82128db3545669_1527752256679_0The difference of two integers equals the sum of the first number and the opposite number of the second one.

Task
The students calculate the difference of the numbers:

a) 6 i (- 7)

b) (- 8) i (- 9)

c) (- 5) i 5

d) 4 i 8.

Task
The students use their skills to solve the text task.

The surface of the water of the lake Genezaret has the altitude of -21 m below sea level. The deepest point of the lake is at 44 m below the surface of the water. What is the altitude of this point?

Task
The students use the difference comparison to  find the number of given properties.

Find the number:

a) less by 5 than – 3,

b) less by 7 than 2,

c) less by 3 than – 3.

An extra task
Wojtek wrote down a number and he subtracted the opposite number of it. As a result he got the negative numbernegative numbernegative number. Was the number Wojtek drew the positive or the negative?

Lesson summarym3e82128db3545669_1528450119332_0Lesson summary

The students do the summarising tasks.

Then they sum up the class drawing the conclusions to memorise:

- The difference of two integers equals the sum of the first number and the opposite number of the second one.

Selected words and expressions used in the lesson plan

addition of the integersaddition of the integersaddition of the integers

difference of the integersdifference of the integersdifference of the integers

integerintegerinteger

negative numbernegative numbernegative number

number less than zeronumber less than zeronumber less than zero

positive numberpositive numberpositive number

subtraction of the integerssubtraction of the integerssubtraction of the integers