Lesson script

Algebra grade 8

Textbook: Yu.N. Makarychev, N.G. Mindyuk, K. I. Neshkov, S. B. Suvorova.

Teacher: G.P. Khlystova

Lesson type: ONZ

Lesson topic: "Standard Number View"

Basic goals:

1) to form knowledge about the standard form of a number;

2) to form the ability to build algorithms using the example of a recording algorithm in a standard form;

3) to form the ability to apply the algorithm when representing numbers in a standard form and actions with them;

Equipment.

Demo material:

Ifa ≠ 0 and n Is a negative integer, then

Equipment: technical equipment of the lesson - a computer, a projector for demonstrating a presentation, a screen. Computer presentation in Microsoft PowerPoint.

DURING THE CLASSES

I.1. Motivation for learning activities

Hello guys!What topic did you work on in the previous lessons? Today in the lesson you will continue to work with the topic “Degree with a whole exponent and will learn something new. Are you ready to discover new knowledge?

How do you always start working in a lesson? (From oral work.)

What tasks do you perform in oral work? (Repetition assignments.)

What is the purpose of the repetition at the beginning of the lesson? (...)

Well done! So what's the next step in the job? (Oral work.)

2. Actualization of knowledge and fixation of difficulties in a trial educational action

Complete the tasks (check on the screen). If you completed the tasks correctly, then you should receive the word - STANDARD.
What is a standard? Where did you meet this word? What does it mean?
Standard (from English -standard ) A sample, a standard, a model with which they are compared, similar objects, processes are compared. (Universal encyclopedic dictionary). That is, when they talk about the standard, it is easier for people to imagine what is at stake.

In the world around us, we are faced with very large and very small numbers.

– Is it convenient to write numbers like this? Why?(Takes up a lot of space, takes a lot of time, and is difficult to remember.)
- What do you think you found a way out of this situation?(Write numbers using powers.)

We already know how to write large and small numbers using the power of the number.

Write down the mass of the earth using the power of a number in different ways. 598 10 25 d. Now write down the mass of the hydrogen atom. 17 10 –20 d. Is it possible to write these numbers differently, using powers? Try it! 59.8 10 26 , 5,98 10 27 ; 0, 598 10 28 ; 5980 10 24 .
17 10 –20 ; 1,7 10 –19 ; 0,17 10 –18 ; 170 10 –21 ;

– All results are correct.

Write down the mass of the Earth and the mass of the hydrogen atom in standard form. What is this task for you?

– Who has no answer? What could not?

– Who has an answer? Justify your answer.

3. Identification of the place and cause of the difficulty

– What was the task before you?

− Some could not, others could not prove. This means that we have a difficulty.

− Let's see what it is.

4. Building a project for a way out of difficulty

What goal will you set for yourself? (Learn how to write numbers in a standard form and learn how to use this method)

– Formulate the topic of the lesson.

What tools can you use to learn something new? (You can use the tutorial, reference.)

– Please open the tutorials on page 211

Possible variant of the plan:

2) Find the definition of the standard form of a number.

3) Think about which signs have multipliers

in the definition.

4) Draw a conclusion what the number could beα .

5) Analyze what a andn .

6) Create an algorithm for writing a number

in standard form

5. Implementation of the completed project

Arrange the steps of the algorithm that is on each table correctly.

Put in the given numberα a comma so that there is one nonzero digit in the whole part.

Determine the sign of the number ordern .

If n> 0, then≥ 10 if n< 0, то 0< < 1 , если n = 0, then 1≤ <10 (If the order is positive, then the number is greater than 10, if - negative, the number is less than 1, and if equal to zero, then the number is in the range from 1 to 10)

– Any positive number can be written in standard form !!!
Why?(By definition. Since the first factor is a number belonging to the interval from)