"Concern about the Environment" PPT Courseware 2

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"Concern about the Environment" PPT Courseware 2

1. Situation introduction

What fraction of the total number of days in the month does the number of days with excellent quality and the number of days with good quality account for?

By what fraction of the total number of days in a month are there more days with good quality than days with slight pollution?

What mathematical information do you know from the picture?

What questions can you ask based on this information?

2. Cooperation and exploration

What fraction of the total number of days in a month does the number of days with excellent air quality and the number of days with good air quality account for?

Answer: The number of days with excellent air quality and the number of days with good air quality account for 9/10 of the total days in the month.

Think about it: What are the similarities and differences between the three calculation methods?

This method has certain limitations. When a fraction cannot be converted into a finite decimal, accurate results will not be obtained.

Both methods convert fractions with different denominators into numbers with the same denominator, but the former is a bit troublesome to draw, while the latter is simpler.

When adding fractions with different denominators, first add the common fractions, and then follow the addition rules for fractions with the same denominator.

3. Independent practice

1. Look at the picture and fill in the blanks.

2. Paint it first, and then write the number.

3. Is the following calculation correct? Mark “√” if it is correct, mark “×” if it is wrong, and correct the incorrect ones.

4. (1) How many kilometers is it from the library to the Children's Palace?

Answer: It is 17/20 kilometers from the library to the Children's Palace.

(2) How many kilometers closer is it to Xiaoming’s house to the library than from Xiaoming’s house to Children’s Palace?

Answer: The distance from Xiaoming’s home to the library is 7/20 kilometers closer than the distance from Xiaoming’s home to the Children’s Palace.

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For more information about the "Concern for the Environment" PPT courseware, please click on the "Concern for the Environment" ppt tag.

"Concern about the Environment" PPT Courseware 3:

"Concern for the Environment" PPT Courseware 3 Teaching Objectives 1. When calculating the addition and subtraction of fractions with different denominators, the fractions must be connected first, and then the calculations must be made according to the addition and subtraction of fractions with the same denominator. 2. Be proficient in the rules of addition and subtraction of fractions with different denominators. Rapeseed and mushrooms account for the total area of ​​this company's main crops...

"Concern for the Environment" PPT courseware:

"Concern for the Environment" PPT courseware teaching objectives 1. When calculating the addition and subtraction of fractions with different denominators, the fractions must be connected first, and then the calculations must be made according to the addition and subtraction of fractions with the same denominator. 2. Be proficient in the rules of addition and subtraction of fractions with different denominators. Rapeseed and mushrooms account for the total area of ​​this company's main crops...

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Update Time: 2024-11-15

This template belongs to Mathematics courseware Qingdao Edition Fifth Grade Mathematics Volume 2 industry PPT template

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