"Positive and Negative Numbers" Rational Numbers PPT Courseware

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"Positive and Negative Numbers" Rational Numbers PPT Courseware

Question 1: The weather forecast stated that the temperature in Beijing on a certain day in December 2003 was -3~3℃. What does it exactly mean? What is the temperature difference in Beijing on this day?

The lowest temperature on this day was minus 3 degrees Celsius, recorded as -3°C. The highest temperature was above zero 3 degrees Celsius, recorded as +3°C. The temperature change on this day was between minus 3 degrees Celsius and above zero 3 degrees Celsius. Here appears A number less than 0.

Question 2: In a football match involving three teams, the red team beats the yellow team (4:1), the yellow team beats the blue team (1:0), and the blue team beats the red team (1:0). How to determine the three teams? Goal difference and ranking order?

The order of football match rankings stipulates: two teams have different points, the team with higher points is ranked first, the team with the same points is ranked first, the team with more goal difference is first, the two teams have the same points and goal difference, the team with more goals is ranked first. Ranked at the top.

Numbers like 10, 1.2, 17... are called positive numbers. They are all larger than 0. The "+" in positive numbers can sometimes be omitted.

Numbers with a "-" sign in front of a positive number are called negative numbers, such as -10, -3...the "-" in negative numbers cannot be omitted.

Representation and pronunciation of positive and negative numbers.

A number with a "-" sign in front of a positive number is represented as a negative number, such as -3, -9, -0.36,

The "+" and "-" signs in front of a number are called their symbols. +3 is read as plus 3 or 3, and -3 is read as minus 3.

In daily life, you will encounter:

1. You walked 5 meters east and 3 meters west;

2. Your father gave you (income) 20 yuan and you spent (expenditure) 8 yuan;

3. The water in the pond rose by 0.01 meters when it rained and dropped by 0.03 meters when it was dry;

4. The temperature is 10 degrees above zero and 6 degrees below zero.

summary:

1. Quantities with opposite meanings and positive and negative numbers

(1) In order to use numbers to express quantities with opposite meanings, we define one meaning of a certain quantity as positive and the opposite meaning as negative. Negative numbers are generated according to actual needs.

(2) 0 is neither a positive number nor a negative number, and positive and negative numbers are bounded by 0.

2. Benchmark

When using positive and negative numbers to express quantities with opposite meanings, in fact, in addition to specifying the positive and negative values, we must also determine what is the basis and record it as 0.

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"Positive and Negative Numbers" PPT courseware:

"Positive and Negative Numbers" PPT courseware Self-introduction: My name is Liu Qing, I am 1.6cm tall, 30 years old, and weigh 51.5 kg. There are boys in our class. Which numbers appeared in the introduction just now? Can you classify them according to the number classification methods you have learned before? Integers and fractions..

"Positive and Negative Numbers" Rational Numbers PPT Courseware 3:

"Positive and Negative Numbers" Rational Numbers PPT Courseware 3 Does 0 only mean none? 1. The number of gold coins in the empty jar; 2. 0℃ in temperature; 3. The height of sea level; 4. Standard water level; 5. Height comparison Benchmark; 6. The boundary between positive and negative numbers; 0 is just a benchmark and it has rich...

"Positive and Negative Numbers" Rational Numbers PPT Courseware 2:

"Positive Numbers and Negative Numbers" Rational Numbers PPT Courseware 2 What are negative numbers? We call numbers with - in front of them negative numbers. So why do we introduce negative numbers? What quantities do we usually use positive numbers and negative numbers to represent in our daily life? Combine the following Short video for us to understand. Practice..

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Update Time: 2024-09-17

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

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