分数乘法的简单运用(Simple application of fraction multiplication)

4分数乘法的简单运用（Simple application of 4 fraction
multiplication）
Simple application of 11. fraction multiplication
Brief tips
Jiangsu primary school mathematics textbooks on the sixth grade, forty-first cases of page 3 and "try", "practice", practice eight item 12-17, "a little bit of a number of a few simple practical problems".
Still to do for example chouhua material, combined with the specific situation, guide the students to use the fractional multiplication learned to solve practical problems related to the understanding of the rich number fraction, lay the foundation for further study to answer practical problems regarding the scores slightly complex. In the process of solving problems, students further cultivate the ability of observation, comparison, analysis and reasoning, and experience the fun of mathematics learning.
Teaching process
Process 1: new knowledge into a
Process 2: new knowledge into b
Process 3: teaching case 3A
Process 4: teaching case 3B
Process 5: teaching case 3C
Process 6: try a
Process 7: try B
Process 8: try C
Process 9: practice and practice a
Process 10: practice and practice B
Process 11: "exercise eight" Twelfth questions a Process 12: "exercise eight" Twelfth questions B Process 13: "exercise eight" thirteenth questions a Process 14: "exercise eight" thirteenth questions B Process 15:, exercise eight, item 14-16, a
Process 16:, exercise eight, item 14-16, B
Process 17: "exercise eight" seventeenth questions a Process 18: "exercise eight" seventeenth questions B Process 19: a full course summary
Paragraph 1: teaching examples 3 and "try""
Teacher: the sixth grade students to do the three colors of silk flower for National Day evening party of various kinds of flowers, flower number shown, please see!
Process 1: new knowledge into a
(look) 3 cases of the sixth grade students to do the three colors of silk flower for National Day evening party of various kinds of flowers, flower number shown.
Teacher: please look at the picture carefully. Can you use the score to describe the relationship between various quantities in the graph? Group classmates say something to each other.
Process 2: new knowledge into b
1. If the yellow flower number "1" as a unit, safflower is yellow, green flower is yellow (); if you put the red flowers as the number of units of "1", yellow is red flowers, green flowers are red;
If the green flower number "1" as a unit, safflower is green flowers, yellow green flowers (is)
Process 3: teaching case 3A
1 (look) flower has 50 more than the yellow flower, safflower, safflower yellow than how many roses?
Please look at the picture: what part of the picture is the number of flowers of safflower more than that of yellow flowers? Who is the result of comparing it with that? What kind of flowers is it?
(courseware) how many flowers are there in safflower than in yellow flowers?
Process 4: teaching case 3B
The red than the yellow, red and yellow flowers are relatively few flower number results. The number of yellow flowers as a unit "1", safflower is more than the number of yellow flowers, that is, 50 flowers.
(courseware) to ask for more safflower than yellow flowers, that is, ask for 50 flowers.
Can you calculate this problem in a row? Write it on your exercise book.
Process 5: teaching case 3C
1 (look) 50 x = 5 (a) a: 5 more than the yellow flower of safflower.
Who says, "what do you think when you make a list?" "Safflower more than yellow flowers", is the number of flowers as a unit "1", safflower more than the number of yellow flowers is 50, that is, for 50 flowers.
Process 6: try a
(courseware) green flowers less than yellow flowers, green flowers less than the number of flowers
Think about the number of "green flowers are less than those of yellow flowers." which number should be considered as "unit 1"? Ask "green flower less than the flower of yellow flower", that is, how many flowers? Please count them independently.
Process 7: try B
Please see the "try" to answer this question. (courseware show) 50 x = 20 (Duo)
Answer: green flowers less than 20 flowers.
Green flowers less than the yellow flowers, here is the number of green flowers and the number of yellow flowers compared to the number of flowers as a unit of "1", seeking green flowers less than the number of flowers, is to ask the 50 is how much.
Process 8: try C
Reflection: what do you think is the key to understanding the quantitative relationship expressed by fractions?
It is pointed out that the key to understanding the quantity relation expressed by fraction is to know which fraction is the result of the comparison of the two quantities. When comparing, the quantity is regarded as unit 1.
The second paragraph: "practice and practice""
Teacher: the students are asked to answer the 2 questions of "practice and practice" independently!
Process 9: practice and practice a
(courseware show).
The little army has 28 stamps, and the smaller ones are more than the small ones. How much is the small force smaller than the small army?
Ask the students to do it independently. Think about the score of each question, which is the result of the comparison of the two quantities, which number is regarded as the unit "1" in comparison? What quantity does the unit "1" mean?
Process 10: practice and practice B
Please answer the two questions of "practice and practice". (Courseware: one by one)
The delta delta delta 2000 2000 2000
The number, the number of more than 5, less than 10.
More than 2000 Delta (2) - A (6), less than a.
Teacher: look at the "practice" the first question left, delta
6, the number of hours is more than a, 6, 6 (a), x = 2, 2 more than the. Look, right, 8, a number of less than 10%, is less 8, 8 x = 6 (a), less than 6 hours.
The little army has 28 stamps, and the smaller ones are more than the small ones. How much is the small force smaller than the small army?
28 x = 8 (Zhang) answer: small force than small army more than 8.
Teacher: the condition of "small force of stamps is more than small army", that is, small force than small army number is small army stamp number, that is, 28, so use 28 x = 8 (Zhang).
Third paragraph: exercises eight to twelfth to 17 questions
Teacher: let's think about some exercises of eight, please!
Process 11: "exercise eight" Twelfth questions a
(look), calculate the following questions, then observed the subject and results, what have you found?
Students are asked to observe the size of each set of scores. After calculating, compare each integral with factor 15 (or 36). Communicate your findings in groups by comparison.
Process 12: "exercise eight" Twelfth questions B
Look at the calculations on the screen, check it out.
(courseware show)
324
15 x = 9 x 36 = 45
2581
Through observation and comparison, it can be found that (1) the number of the courseware is multiplied by the fraction greater than the 1, and the result is larger than the original number; a number is multiplied by the fraction smaller than 1, and the result is smaller than the original number.
Process 13: "exercise eight" thirteenth questions a
(courseware show)
Ask the students to observe characteristics of each multiplication formula, with twelfth questions found in law, directly determined with two channel formula data size. Direct judgment, you can also be verified by further calculation.
Process 14: "exercise eight" thirteenth questions B
Look at the results of each of the algorithms presented on the screen. (courseware show)
X 16 < 16 x 13 < < 13
X 15 > 14 x 36 x = x 36
Who said, the two questions in front of you, what do you think?
Process 15:, exercise eight, item 14-16, a
Now please carefully and answer the following questions independently. (courseware show)
We first talk about the scores of all the significance of the relationship between the number of complete type.
The ball the number of football more than.
The number of (x) = x ()
The actual water consumption than planned savings.
Water consumption (x = ())
There are 24 classes in the new primary school can last year, this year to expand the scale, increase the number of classes than last year. How many classes have been added this year?
, a sweater, price 56 yuan, now the price lower than the original. How much is the price reduction?
Process 16:, exercise eight, item 14-16, B
Let's look at the answers to these questions together. (Courseware: one by one)
We first talk about the scores of all the significance of the relationship between the number of complete type.
The ball the number of football more than.
The number of (football) = (ball is more than football)
[teacher: the number of balls is more than football, and the number of football is regarded as the unit "1"
The actual water consumption than planned savings.
(planned) water consumption x = (actual saving) water consumption
[Division: the actual water consumption is less than the original plan, the original planned water consumption as unit "1"]
There are 24 classes in the new primary school can last year, this year to expand the scale, increase the number of classes than last year. How many classes have been added this year?
24 x 9 (a) answer: 9 classes have been added this year.
[teacher: "this year than last year," is the result of this year's class number compared with last year, the number of classes last year as a unit "1", "this year increased the number of classes", is to ask "24 is how much"
, a sweater, price 56 yuan, now the price lower than the original.
How much is the price reduction?
56 x = 16 (yuan) answer: 16 yuan reduction.
[teacher: the question of "how much is the price reduction" is the result of comparing the present price with the original price. The original price is regarded as the unit "1", and the "how much is the price reduction" is to ask "how much is 56 yuan"?
Group students combine the specific circumstances of the fifteenth, sixteenth questions, and then say to each other: each fraction in the question is the result of the comparison of the two quantities Which number is regarded as the unit "1"? What quantity does the unit "1" mean?
Process 17: "exercise eight" seventeenth questions a
Ask the students to answer them individually. What's the difference between them?
Process 18: "exercise eight" seventeenth questions B
Now look at the answer to the two question of the seventeenth question. (courseware show)
In the school bought 24 volleyball, football volleyball more than buy. How much football do you buy more than volleyball?
24 x = 6 (x)
Answer: 6 more football than volleyball.
The school bought 24 volleyball, football volleyball is bought. How many soccer balls did you buy?
24 x = 30 (x)
Answer: bought 30 football.
Please think about it: why do all these two problems use multiplication? The first problem is known to buy football than volleyball, volleyball as the number of units of "1", how much more football than volleyball, is to ask what is the 24? The problem is the number of known football is volleyball, volleyball or the number of units as "1", and bought a number of football, is to ask how much is 24.
These two questions are "how much is a fraction of a number", so it can be calculated by multiplication.
The fourth paragraph: summary of the whole lesson
Process 19: a full course summary
What do you learn from this lesson? How are you doing in your class today?
One。