"Understanding Decimals" PPT teaching courseware for preliminary understanding of decimals

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"Understanding Decimals" PPT teaching courseware for preliminary understanding of decimals

Part One: Introduction to the topic

1. Review old knowledge

fill in the blank:

1 Yuan = ( ) Jiao 90 Jiao = ( ) Yuan

7 jiao = ( ) minute 200 cm = ( ) meter

30 decimeter = ( ) meter = ( ) centimeter

2. Please read the text accompanying the picture and collect relevant mathematical information.

[Answer] Ham sausage is 5.98 yuan each, milk is 0.85 yuan per bottle, and bread is 2.65 yuan each.

Today, let’s discuss knowledge about decimals.

Understanding Decimals PPT, Part 2: New Teaching Knowledge

Example 1: 3.45, 0.85, 2.60. How are these numbers different from the numbers we have learned before?

[Answer] There are no dots in the middle of the numbers I have learned before. There is a small dot in the middle of these data.

[Conclusion] Numbers like 3.45, 0.85, 2.60...that have a small dot in the middle are a new type of number - decimals.

Example 2: 3.45, what do you know about decimals?

[Answer] 3.45 is pronounced as three point four five; with the decimal point as the boundary, the part before the decimal point is the integer part, and the part after the decimal point is the decimal part.

[Conclusion] The small dot in the middle of the decimal is called the "decimal point", pronounced "dot". The decimal point is an important symbol of decimals. In decimals, the integer part and the decimal part are read differently. The integer part is read as an integer, and the decimal part only needs to be read each number in order.

Key points of knowledge

1. Numbers like 3.45, 0.85,...are all decimals. The decimal point is an important symbol of decimals.

2. How to read decimals: 3.45 is read as three point four five, 0.85 is read as zero point eight five...

3. One decimal place can be expressed as tenths, such as: 0.1=1/10, 0.3=3/10.

4. Two decimal places can be expressed in percents, such as: 0.03=3/100, 0.18=18/100.

Understanding decimals PPT, the third part: knowledge sorting

Knowledge point 1: Understand decimals and how to read decimals.

Example 1: 3.3 is pronounced as _________; 0.63 is pronounced as _________.

[Answer] 3.3 is pronounced as three point three and 0.63 is pronounced as zero point six three.

[Analysis] When reading 3.3, the integer part 3 of the decimal is read as an integer, the integer part of 0.63 is read as zero, the decimal point in the middle is read, and the numbers after the decimal point are read in order from left to right. For example, 3.3 is read as three point three; 0.63 is read as zero point six three.

Little exercise: I can read.

18.89 is pronounced: ____________________.

20.70 is pronounced: ____________________.

0.33 is read as: ____________________.

120.43 is read as: ____________________.

100.36 is read as: ____________________.

Knowledge point 2: How to write decimals.

Example 1: Six eighty-nine is written as ________; zero two-four is written as ________?

[Answer] Six point eighty-nine is written as 6.89; zero point two-four is written as 0.24.

[Analysis] When writing six point eight nine, first write the integer part of six, then write the decimal point after the integer, and finally write eight and nine in sequence. When writing zero point two four, write the zero in the integer part first, then write the decimal point after zero, and finally write two and four in sequence.

Understanding decimals PPT, Part 4: Classroom exercises

1. Fill in the blanks.

(1) 1 yuan = 10 jiao, 5 jiao is ()/() yuan, and can also be written as () yuan.

(2) 1 yuan = 100 points, 5 points is ()/() yuan, and can also be written as () yuan; 36 points is ()/() yuan, and can also be written as () yuan.

(3) 3 yuan and 50 cents written as a decimal is ( ) yuan; 5 jiao and 8 cents written as a decimal is ( ) yuan.

(4) Three five-yuan notes and one five-yuan coin are ( ) yuan.

2. Judgment. (Draw "√" if correct and "×" if incorrect)

(1) 2.36 is read as two thirty-six. ( )

(2) Zero point four and five writing: 0.45. ( )

(3) There are 4 tenths in 0.4. ( )

(4) Three ten-yuan cards and three five-cent cards are 31.5 yuan. ( )

3． Read the decimal on the line below.

(1) An elephant weighs approximately 3.56 tons. _______________________

(2) An ostrich runs 55.63 kilometers per hour. _______________________

(3) Their scores differ by 0.35 points. __________________

Understanding decimals PPT, Part 5: After-class exercises

1. Look at the picture and fill in the appropriate fractions or decimals.

2. Read the decimal on the horizontal line below.

(1) The total length of Nanjing Yangtze River Bridge is 6.78 kilometers. _______________________

(2) 1 kilogram of seawater contains 0.03 kilograms of salt. _______________________

(3) Dad is 0.36 meters taller than Xiaohong. ____________________

(4) A wooden stick is 3.26 cm longer than an iron rod. _______________________

3． Divergent thinking.

Use five cards "6, 0, 0, 3" and "." to form different numbers. Please write them as required.

(1) Not a single zero is read and the decimal part is one decimal place.

(2) Only one zero is read and the decimal part is two decimal places.

(3) Read two zeros and the decimal part is three decimal places.

【Answer】(1) 600.3 (2) 60.03 (3) 6.003 or 3.006

Keywords: Free download of PPT courseware for mathematics in the second volume of the third grade of the People's Education Press, download of PPT on understanding decimals, download of PPT on preliminary understanding of decimals, .PPT format;

For more information about the PPT courseware "Preliminary Understanding of Decimals and Decimals", please click the "Preliminary Understanding of Decimals" PPT tag.

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Update Time: 2024-09-30

This template belongs to Mathematics courseware People's Education Press third grade mathematics volume 2 industry PPT template

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