Lesson No. 24 12/11/2014 Algebra Grade 8 Shevchuk E.I.
Lesson topic:
STANDARD NUMBER
Lesson Objectives:
Cognitive:
1. To acquaint students with writing numbers in a standard form and use the obtained values when solving problems. Establish interdisciplinary connections.
2. Show how to write large and small numbers.
3. To form the ability to synthesize and generalize the knowledge gained.
4. Show the importance of the topic in the study of related disciplines.
5. Develop in students cognitive interest to the subject.
Developing:
to develop in students thinking, speech, memory, the ability to highlight the main thing,continue to develop the ability to analyze.
Educational:
to cultivate a common culture, activity, independence, ability to communicate, patriotism.
Lesson type:
a lesson of explanation and primary consolidation of new knowledge.
Equipment:
itinerary,
technical equipment lesson - computers,
computer presentation in Microsoft PowerPoint.
Teaching methods:
according to the source of acquired knowledge - verbal, practical, visual;
by level cognitive activity- problematic, partially exploratory.
Lesson form: practical lesson.
“The road will be mastered by the walking one ...!”
DURING THE CLASSES:
- Organization of the beginning of the lesson
Hello! Check, please,their readiness for the lesson.
And now let's turn to the epigraph of our lesson “The road will be mastered by the walking ...!”
What do these words mean?
Each of you will receive a route sheet in which he will fix his work and at the end of the lesson will evaluate it.
(Route sheets are distributed)
Slide #1
Vitamins, minerals, foods.
(Task number 1 on ML)
The correct answers are written on the back of the board.
Self-test. Slide #2-3
We collect points.
IIMessage about the topic and purpose of the lesson
Slide #4
– Before you start learning a new topic, complete the tasks on the first page of the route sheet (check on the screen).If you completed the tasks correctly, then you should receive the word - STANDARD.
What is a standard? Where did you come across this word? What does it mean?
(The very first task on the ML table)
Slide #5
Standard (from English - standard) A sample, standard, model with which similar objects, processes are compared, compared. (Universal Encyclopedic Dictionary). That is, when talking about the standard, it is easier for people to imagine what is at stake. And today we will talk about the standard form of a number. So, this is the topic of today's lesson.
slide number 6
- Updating students' knowledge.
Preparation for active educational and cognitive activity at the main stage of the lesson
In the world around us, we encounter very large and very small numbers. We already know how to write large and small numbers using the degree of a number.
IV.Assimilation of new knowledge
Slides No. 7-8
Is it convenient to write numbers in this form? Why? (Take up a lot of space, waste a lot of time, hard to remember.)
- How What do you think is the way out of this situation? (Write numbers using powers.)
(Task number 3 on ML)
Use of the conceptdegree makes the expression shorter and more compact.
Especially often degrees are used when writing big numbers. Such numbers are written using a power with base 10. For example:
10 -1 = 0,1
10 0 = 1
10 1 = 10
10 2 = 100
10 3 = 1000
!!! The base 10 exponent tells you how many zeros to write after the 1.
For example, the radius of the globe, approximately equal to 6.37 million m, is written as 6.37 10 6 m
Degree 10 6 equals 1,000,000 so:
6.37 10 6 m = 6,370,000 m
In addition, the notation of numbers using a degree is used to write natural numbers assums of bit terms.
4 835 = 4 1000 + 8 100 + 3 10 + 5 = 4 10 3 + 8 10 2 + 3 10 + 5
!!!
Every number greater than 10 can be written in standard form:
a 10 n , where 1 ≤ a ≤ 10 and n is a natural number.
Such a notation is called the standard form of a number.
Slide #9
Write down the mass of the Earth using a power of a number. 598 10 25
d. Now write down the mass of the hydrogen atom. 17 10-20 g. Is it possible to write these numbers differently using degrees? 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. But is it possible to speak of a standard notation? How to be? (Agree on a single notation of numbers.)
- Try to discuss with a neighbor what kind of record should be a single, standard one?
- What should be the factor before the power of the number 10, so that it is convenient to REMEMBER the number andimagine it?
- Please openslide number 10
And textbooks n 11 p.104, find the definition of the standard type of number and write it down in the route sheets.
– Standard type of number calledrecord of the form a 10n, where 1< a< 10, n – целое. n – называют порядком числа.
– In standard form, you can write any positive number!!!
Why? (By definition. Because the first factor is a number that belongs to the interval from )