"Fraction" PPT courseware 2

Description

"Fraction" PPT courseware 2

Teaching objectives, key points and difficulties

Able to use fractions to express quantitative relationships in real situations,

Understand the model idea of ​​fractions and further develop the sense of symbols.

Understand the concept of fractions and clarify the difference between fractions and integers.

In the problem of land desertification,

Understand the importance of protecting the human living environment.

Understand the form of fractions, and understand a feature of the concept of fractions: the denominator contains letters; a requirement: the values ​​of letters are limited to such that the value of the denominator must not be 0.

Find a condition under which the fraction is meaningful.

1. How to express the division of the following two integers in the form of fractions:

3÷4=_____, 10 ÷ 3=_____,

12 ÷11=_____, -7 ÷2=_____ .

2. In algebraic expressions, the division of integers can also be expressed similarly.

Try expressing the division of the following integers in fraction-like form:

⑴ 90÷x can be expressed by the formula _____.

60÷(x-6) can be expressed by the formula _____.

(2) A total of m tons of wheat is harvested from n hectares of wheat fields,

The average yield per hectare can be expressed by the formula _____ tons.

1. When x takes what value, do the following fractions make sense?

(1)8/x-1 (2) 1/x²-9

Solution ⑴: From the denominator x-1=0, we get x=1.

So when x≠1, the fraction 8/x-1 makes sense.

(2): From the denominator x2-9=0, we get x=±3.

So when x≠±3, the fraction 1/x²-9 makes sense.

Enlightenment and reflection

1. What did you gain from this class?

2. What formulas have you learned so far? Can you give some examples?

3. What is the basis for distinguishing integers and fractions? Are there any conditions for the fraction to be established?

Study method guidance:

A fraction is a model that represents a quantity in a specific situation, and a fraction is a fraction

Algebraic, so its properties and operations are completely similar.

Mathematics (fractions) is closely related to the real world.

In the past, letters were used to express quantitative relationships as integers, but in the future, expressions used to express quantitative relationships could be fractions.

Keywords: Fraction courseware, New People's Education Edition eighth grade mathematics PPT courseware, eighth grade mathematics slide courseware download, fraction PPT courseware download, .ppt format

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Update Time: 2024-09-13

This template belongs to Mathematics courseware People's Education Press Eighth Grade Mathematics Volume 1 industry PPT template

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