Lesson topic:
The standard form of a number. 8th grade
Learning objective of the lesson:
explain the terms "standard form of a number", "order of a number";
teach any positive number to represent in a standard form;
via test items check the ZUN of students on the previous topic, as well as consolidating a new topic;
to continue work on self-training, self-control, mutual control,
pay attention to interdisciplinary communication .
Development goal:
Continue developing the ability to highlight the main, essential in the material being studied, to summarize the facts studied.
Continue the development of logical thinking.
Develop cognitive interest students to the subject.
educational goal:
1. Education of the will, the ability to bring what has been started to the end, to overcome difficulties.
To form a self-esteem of knowledge, a critical attitude towards oneself, creative activity, accuracy, discipline, attention.
Expand your understanding of the world around you.
Lesson type: a lesson of explanation and primary consolidation of new knowledge.
Teaching methods: according to the source of acquired knowledge - verbal, practical, visual;
by level cognitive activity- problematic, partially exploratory.
Equipment: route sheet (MR); technical equipment lesson - a computer, a projector for demonstrating a presentation, a screen. Computer presentation in Microsoft PowerPoint.
DURING THE CLASSES
I. Organization of the beginning of the lesson (7 min)
Good afternoon friends! I am glad to see you and really want to start working with you. Have a good mood and success! Is everyone ready for the lesson?
Children: Yes!
Teacher: Then go ahead!
Please check that you have handouts on your desk and that you are ready for the lesson.
What topic did we study in the last lesson?
Properties of powers with a negative integer exponent.
Blitz survey.ML1slide1
II. Reporting the topic, goals and objectives of the lesson (5min)
– 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? (SCREEN). Standard in the Encyclopedic Dictionary:
Standard - (from English standard - norm- sample), in the broadest sense words-sample, reference, model, taken as initial for comparison with other similar objects. Standard as a normative and technical document establishes complex norms, rules, requirements for the object of standardization. Standard maybe to be designed as a tangible items(products, standards, samples of substances), and on the norms, regulations, requirements in different areas. An education standard is an official document with a list of requirements that are mandatory for educational institutions accredited by the state. 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. We have decided on the topic, but what goal will we set for ourselves?
Student answers:
What record is called standard;
Learn how to represent a number in standard form;
Where such a notation of a number is used;
Why was such a record necessary?
III. Actualization of students' knowledge. Preparation for active learning cognitive activity at the main stage of the lesson (10 min)
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. 5.98 10^24 kgEarth: 5.98.10^21 t
Is it convenient to write numbers in this form? Why? (Take up a lot of space, waste a lot of time, hard to remember.)
What do you think is the way out of this situation? (Write numbers using powers.)
Write down the mass of the Earth using a power of 598 10 25 g. Now write down the mass of the hydrogen atom. 17 10–20 d. Is it possible to write these numbers differently using degrees? Try it! 59.8 10 26 , 5.98 10 27 ; 0.5981028; 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 and present it?
IV. Assimilation of new knowledge (7 min)
- Please open the textbooks p. 35 p. 187 and find the definition of the standard type of number and write it down in the route sheets.
- The standard form of a number is a record of the form but 10 n , where 1 but
Algorithm
Move the comma so that the integer part of the number but was 1≤a
2. Express 10 as a positive power if the comma was moved to the left and as a negative power if the comma was moved to the right.
3. Represent the number as a ∙ 10 n
What is the order of the number? A large positive order gives an idea of how large and a large modulo negative order tells how small a number is. For example: if the order is 3, then this means that 1000≤α
ML3Find the definition of the standard type of number from the textbook and write it down in the route sheet.
What number can be written in standard form?
– 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 )