"Inequality" PPT courseware

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"Inequality" PPT courseware

Part One: Quotations:

1. As shown in the picture, an object A is placed on the left side of the balance, and weights are placed on the right side (each weight weighs 1 gram).

(1) In Figure (1), it can be seen that the weight of object A is ____ grams. That is: the weight of object A is _____2 grams. (greater than less than)

2. According to the weather forecast, today's highest temperature is 10℃. The lowest temperature is -5 ℃, so we can say that the temperature on this day is not lower than ___ ℃ and not higher than ___ ℃

3. Counting the ages of the whole class, the oldest one is 16 years old, so we can know that the age of every student in the class is ___17 years old. (bigger than smaller than)

Question: If today's temperature is t ℃ and the age of a classmate is a years old, can you express these unequal relationships using formulas?

4. Song Hongliang's weight a kilogram is not equal to Meng Ya's weight b kilogram.

Question: How to express this inequality relationship using a formula?

Inequality PPT, Part 2: Do it

1. Which of the following expressions are inequalities? What are the equations?

(1)x-20 (3)3x²+2x

(4)x=2x+5 (5)a+b≠c (6)|x-1|≥0

2. Use ">" "<" or "≥" "≤" to fill in the blanks

(1)4___-6 (2)-4.5__-4

(3)3×(-1) __ 2×(-1) (4) x²+1 __ 1

Inequality PPT, the third part: explore together

There are two trucks, large and small, transporting goods from point A to point B. The driving speed of the large truck is 55km/h, and the driving speed of the small truck is 65km/h. The large truck starts 1 hour earlier than the small truck. How many hours does it take for a small truck to pass a large truck?

1. If the traveling time of the small truck is X h, then how should the distance it travels be expressed? At this time, how does the distance traveled by the large truck be represented?

The distance traveled by a small truck is expressed as: 65X km

The driving distance of the large truck is expressed as: 55 (X+1) km

2. After the small truck overtakes the large truck, how should the relationship between the distances traveled by them be expressed?

65X>55(X+1)

Solution: Suppose the small truck catches up with the big truck after driving X hours.

65X= 55(X+1)

X=5.5

Answer: Because when the small truck takes 5.5 hours to catch up with the big truck. So when the small truck drives 5.5 hours later it overtakes the big truck.

Part 4: You can do it

1. Determine which of the following expressions are inequalities? Which ones are not?

① 3>2;② x+3<5;③ 4>6;④ 2x+1;

⑤ 5x+2=7x ⑥ a≠3⑦ 2x+3y≤9

Among the inequalities are _____________;

There are ___________ that are not inequalities.

2. Express it as an inequality:

(1) The sum of 3 times x and 5 times y is not greater than 3.

(2)x is a positive number.

(3)x is a non-negative number.

(4)a is not less than b.

(1)3x+5y≤3.(2)x>0. (3) x≥0. (4)a≥b

3. The original height of a certain tree is 1.7 meters. If it grows x meters per year on average in the future, the height of the tree will exceed 2.6 meters in four years. Then the inequality satisfied by x is ______.

4. Among the following numbers, which of them can make the inequality 4x-3≤7 true ( )

A. 7 B. 5 C. 3 D. 1

5. Which of the following numbers -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5 satisfy both the inequality x+5<7 and 2x+2<0 How many numbers?

Inequality PPT, Part 5: Reflection and Evaluation

1. Definition of Inequality.

2. Can use inequalities to express simple quantitative relationships.

3. Know that there are many values ​​for which an inequality holds.

Ability Challenge

As shown in the figure, ropes of length l� are used to form a square and a circle respectively.

(1) If the area of ​​the square is to be no larger than 25�2, what relationship should the rope length l satisfy?

(2) If the area of ​​the circle is to be greater than 100�2, what relationship should the rope length l satisfy?

(3) When l=8, which one has the larger area, the square or the circle? What about l=12 and l=20?

(4) Change the value of l and try again. What inspiration can you get from this process?

Keywords: Free download of Hebei Education Edition mathematics PPT courseware for seventh grade volume 2, inequalities PPT download, .PPT format;

For more information about the "Inequality" PPT courseware, please click the Inequality ppt tab.

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Update Time: 2024-11-21

This template belongs to Mathematics courseware Hebei Education Edition Seventh Grade Mathematics Volume 2 industry PPT template

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