"Evaluation of Algebraic Expressions" Integers and their addition and subtraction PPT courseware 3

Description

"Evaluation of Algebraic Expressions" Integers and their addition and subtraction PPT courseware 3

Expressed algebraically:

(1) 3 times the sum of x and 5 ________

(2) The number that is 1 more than the square of the difference between a and b is ___

(3) 5 times the sum of A’s number and half of the sum of B’s number _____

(4) A two-digit number, the number in the ones place is b, and the number in the tens place is a. This two-digit number can be expressed as _____

Teaching process

As the value of n increases, the value of each algebraic expression increases.

The value of n² first exceeds 100, because when n=6, the value begins to exceed the value of 5n+6.

The evaluation of algebraic expressions can infer the laws reflected by each algebraic expression, and different algebraic expressions reflect different laws.

step

1. Write the value of the letter, that is, "when...".

2. Write the algebraic expression of the required value.

3. Substitute the values ​​of the letters into the same letters in the algebraic formula, and obtain the calculation result according to the operation relationship.

Notice

1. You can also substitute first and then calculate. The substitution step is essential.

2. In the process of substituting numbers into letters, sometimes it is necessary to add operational symbols or brackets appropriately. For example, a multiplication sign should be added to the multiplication relationship between numbers. When substituting negative numbers, brackets should be added. When the base of a power is a fraction or a negative number, it The base of must be added in parentheses.

Practice in class

1. The mass of human blood accounts for approximately 6% to 7.5% of human body weight.

(1) If someone weighs a kilogram, what is the approximate range of his blood mass?

(2) Liangliang’s weight is 35 kilograms. What is the approximate range of his blood quality?

(3) Estimate your own blood quality?

Lesson Summary

Through the study of this lesson, we will find the value of an algebraic expression. For an algebraic expression, when the letters it contains take different values, the value of the algebraic expression will generally be different, so when finding the value of the algebraic expression, you must pay attention to solving the problem. step:

(1) Indicate the value of the letter.

(2) Copy algebraic expressions

(3) Substitution.

(4) Calculation.

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For more information about the PPT courseware "Integers and their addition and subtraction of algebraic expressions" PPT courseware, please click the "Integers and their addition and subtraction ppt evaluation of algebraic expressions" ppt tag.

"Evaluation of Algebraic Expressions" Integers and their addition and subtraction PPT courseware 2:

"Evaluation of Algebraic Expressions" Integers and their addition and subtraction PPT courseware 2 Review 1. The single digit of a two-digit number is a, and the tens digit is b. Please use an algebraic expression to express this two-digit number; 2. How to use an algebraic expression to express a three Number of digits? 3. What can the algebraic formula (1+8%)x represent? ..

"Evaluation of Algebraic Expressions" Integers and their addition and subtraction PPT courseware:

"Evaluation of Algebraic Expressions" PPT courseware on integers and their addition and subtraction. Do it: According to medical research, the mass of human blood accounts for about 6% to 7.5% of human body weight. ⑴If someone weighs a kilogram, what is the approximate range of his blood mass? ⑵Liangliang’s weight is 40..

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Update Time: 2024-06-30

This template belongs to Mathematics courseware Beijing Normal University seventh grade first volume mathematics industry PPT template

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