The first unit courseware of the sixth grade mathematics 1 teaching objectives;
1. On the basis of students' existing fractional addition and the basic meaning of fractions, combined with life examples, students can understand the meaning of fractional multiplication by integers, master the calculation method of fractional multiplication by integers, and skillfully use the calculation rules of fractional multiplication by integers to calculate.
2. Through observation and comparison, guide students to sum up the calculation law of fractional multiplication by integer through experience, and cultivate students' abstract generalization ability.
3. Guide students to explore the internal relationship of knowledge and stimulate students' interest in learning. Through demonstration, students can have a preliminary understanding of arithmetic, and feel the charm and beauty of mathematical knowledge in this process.
Teaching emphasis: make students understand the meaning of fractional multiplication by integer and master the calculation method of fractional multiplication by integer.
Teaching difficulties: guide students to summarize the calculation rules of fractional multiplication by integer.
Teaching process:
pave the way
1. Show the review questions. (slide)
What does (1) mean by integer multiplication?
(2) List and tell the meanings of multiplicand and multiplier in the formula.
What is five 12? How much is nine 1 1? How much is eight sixes?
(3) Calculation:1/6+2/6+3/63/10+3//kloc-0+3//0.
When calculating 3/10+3/10+3/10, ask the students: What are the characteristics of this problem? What is the molecule in calculation? Let the students see that all three addends are the same. When calculating, the result of three consecutive additions is the numerator, and the denominator remains unchanged.
2. Lead the topic.
Is there a simple algorithm for fractional addition? Today we are going to learn fractional multiplication. (Title on the blackboard: Fractions multiplied by integers)
(2) Explore new knowledge.
1. The meaning of multiplying teaching scores by integers. Give an example of 1 and read the questions by name.
(1) Analysis and demonstration: Teacher: Everyone eats 2/9 cakes. Is it enough for everyone? (Not enough) Then show three pie charts like a textbook. Q: How many 2/9 pieces did three people eat? Let the students see from the picture that three people ate three 2/9 pieces. Ask the students to use what they have learned before to answer how many pieces did three people eat? The teacher drew braces under the three sectors and marked them? When revising, the teacher wrote on the blackboard:
2/9+2/9+2/9 = 2+2/9 = 6/9 = 2/3 (block), (The teacher put three double-layer fan-shaped pictures together to make two thirds of a cake)
(2) observation and guidance:
What are the characteristics of the three addends in this question? Let the students see that the scores of the three addends are the same. The teacher asked: How to find the sum of three identical scores is easier? Guide students to enumerate multiplication formulas. Teacher's blackboard writing:
2/9×3。 Then inspire students to say that 2/9×3 means to find the sum of three 2/9 additions.
(3) Compare the similarities and differences between 2/9×3 and 12×5:
Tip: Compare the meanings and characteristics of the two formulas. Let the students discuss. Through discussion, students can draw the following conclusions:
Similarity: These two expressions have the same meaning.
Difference: 2/9×3 is a fractional integer, and 12×5 is an integer multiplied by an integer.
(4) Summary:
The teacher made it clear that these two expressions have the same meaning. Who can sum up the meaning of these two expressions in one sentence? Guide the students to say that they all mean finding the sum of several identical addends. )
2. The calculation rules of multiplying teaching achievement by integer.
(1) deduction algorithm:
Multiply the meaning of an integer by a fraction.
Q: What does 2/9×3 mean? Guide the students to say that they want three 2/9 sums. Student calculation, hint: how to write a simple method of adding three twos in a molecule? Write the answers on the blackboard: 2×3/9=6/9=2/3 (block) Teacher's Note: The addition formula in the middle of the calculation process is to illustrate the calculation, which is omitted. (adding dotted lines while talking)
(2) Guided observation: What is the relationship between the numerator and denominator of 2×3/9 and the two numbers in formula 2 × 9 × 3? (discuss with each other)
Observation results: the molecular part of 2×3/9, 2×3, is the numerator 2 of 2/9 multiplied by the integer 3 in the formula, and the denominator has not changed.
(3) Summary: Please summarize the calculation method of 2/9×3 according to the observation results. (discuss with each other)
Report results: (Let more students report) Let students draw the conclusion that 2/9×3 is the product of numerator 2 of fraction 2/9 multiplied by integer 3 as numerator, and the denominator remains unchanged. according to
In the calculation of 2/9×3, it is clearly pointed out that the numerator and denominator can be divided first and then multiplied. The approximate number after reduction should be aligned with the original number up and down. Then let the students calculate 2/9×3 in a simple way.
3. Feedback exercise:
1) Title 1 on page 2 of the textbook.
When correcting mistakes, let the students say what the multiplicand and multiplier in multiplication mean.
2) The second question of "Do something" on page 2 of the textbook.
Teacher's tip: When multiplying, if the numerator and denominator are divisible, divide the points first.
3) Exercise 1 the first 1, 2, 3 on page 6 of the textbook.
Students complete independently and communicate collectively. Let the students talk about their ideas.
(3) class summary.
In this lesson, we learned the knowledge of multiplying fractions by integers. In multiplication, we use the product of numerator multiplied by integer as numerator, and the denominator remains unchanged. What can be reduced can be reduced first and then calculated, and the result is the same.
Write on the blackboard.
Integer decimal multiplication
2/9×3=2×3/9=6/9=2/3
Fraction multiplied by integer, the product of numerator multiplied by integer is numerator, and denominator remains unchanged.
Teaching reflection:
The sixth grade mathematics volume I 1 unit courseware 2 teaching objectives:
1, understand the meaning of fractional multiplication, master the calculation rules of fractional multiplication, and learn the simple calculation of fractional multiplication.
2. Cultivate students' ability of analogy and induction through mathematical activities such as migration, analogy, induction and communication.
3. Through the application examples of multiplying scores by scores, educate students to take learning as the purpose and stimulate their learning motivation and interest.
Teaching emphasis: understand the meaning of a number-multiplied fraction and master its calculation rules.
Teaching difficulty: understanding the meaning of multiplying a number by a fraction.
teaching process
First, create situations and introduce new lessons.
1, creating a situation: Uncle Li's family has a piece of land of 1/2 hectares. The area planted with potatoes accounts for 1/5 and the area planted with corn accounts for 3/5.
What questions can you ask according to the information given in the topic?
Default: How many hectares is the potato planting area? How many hectares of corn have been planted?
(1) Understand the meaning: this land * * * has 1/2 hectares, and the potato planting area accounts for 1/5 of this land. We should look at the area of this land.
Unit "1". 1/2 What is the potato planting area? By multiplication, the formula is 1/2 × 1/5.
2. Disclosing the topic: Please follow the formula 1/2 × 1/5. What are its characteristics?
Second, discuss communication and solve problems.
(1) Operation of inquiry.
1, Question: What is 1/2 × 1/5?
2. Put forward the operation requirements: this paper represents the vegetable field with an area of 1 hectare. Please cooperate with your group for one dose and one garment, indicating1/2×1/5 =110.
3. Students begin to operate and teachers patrol.
4. The group reported the research results.
First, fold the whole paper in half and divide the paper into two parts, each part is 1/2 of this paper. Then divide the 1/2 into five parts and draw the 1 part, which accounts for110 of the whole paper. Description1/2×1/5 =110.
5. Combine with demonstration.
Demonstrate the coloring process: First, we divide the paper into two parts, 1 is the paper's 1/2, and then divide the paper into five parts, that is, we divide the paper into 2× 5 = 10, and 1 is the paper's 65438+. From this, we can get:1/2×1/5 =1×1/5× 2 =10 (blackboard formula).
(2), migration extension, induction law.
1, understand the meaning of the problem: and solve the problem
The method of (1) is the same. The area planted with corn accounts for 3/5 of this land (1/2 hectares), which can also be regarded as the unit of "1". To find the area for planting corn is to find the 3/5+0/2 hectare of 65438 and multiply it.
2. Group discussion and operation: how to form it? Coloring represents 3/5+0/2 of 65438. How to calculate?
3.AC calculation methods and ideas.
Default: As before, this paper is divided into 2× 5 = 10, but the difference is that 3 copies are taken to get:1/2× 3/5 =1× 3/2× 5 = 3/10.
(blackboard formula)
4. Question: Looking at these two formulas on the blackboard, can you talk about the calculation method of multiplying the score by the score?
5. Through students' discussion and communication, we can get the following results: the product of the score multiplied by the score, the product multiplied by the numerator is the numerator, and the product multiplied by the denominator is the denominator.
Third, consolidate application and improve internalization.
1, questions 1 and 2 of "doing" on page 4 of the textbook.
2. 4/9 of 1/3 is (), and 3/4 of 1/5 is ().
3, a piece of land is 4/5 hectares, and the 1/7 of this piece of land is () hectares.
4. The weight of a pile of cement 15/ 16 tons, 3/7 tons used, () tons used, multiplied by the total ().
5. 1 kg of noodles 3/2 yuan, Aunt Wang bought 7/1kg of noodles, and * * * spent () yuan.
6. The width of a rectangle is 5/18m, and the length is four times the width. The area of this rectangle is () square meters.
Fourth, review and improve.
Fraction multiplied by fraction, the product of molecular multiplication is a molecule. The denominator is the product multiplied by the denominator.
Blackboard writing:
Score times score.
1/2× 1/5= 1× 1/2×5= 1/ 10
1/2×3/5= 1×3/2×5=3/ 10
Fraction multiplied by fraction, the product of molecular multiplication is a molecule. Use the product of denominator multiplication as the denominator.
Teaching reflection:
The sixth grade mathematics volume 1 1 unit courseware 3 teaching objectives:
1. Consolidate students' mastery of calculation methods and improve their calculation ability.
2. Further grasp the significance of fractional multiplication.
3. Cultivate students' good habits of examining questions and calculating.
Teaching emphasis: improving computing ability.
Teaching difficulty: grasping the significance of fractional multiplication.
teaching process
First, import
1, oral calculation
1/4× 1/3 1/5× 1/2 2/3×3/4 2/5× 1/2
14×3/7 15×4/5 5/8×2/5 7/ 15×5
2,4/11× 5 means ().
10×3/5 means ().
Second, consolidate practice.
1, calculating
7/33×3/ 14 5/7×4 27×5/9
5/8×4/ 15 7/ 12×3/7 14×6/7
Students finish independently and revise collectively. When reporting, ask students to say the meaning of liquidation first, and then talk about the calculation process.
2, column calculation
How many tons are two thirds of 9/ 10?
How many meters is 0/2 of 65438+5/8 meters?
How many kilograms is half of 9 kilograms?
Students finish independently, talk at the same table, report collectively, and emphasize understanding "half".
3. 1kg milk contains lactose 1/2 1kg and protein content is 7/ 10. 1kg How many kilograms of protein does milk contain?
Students complete the exercises in groups.
Third, summary.
Through today's exercise, I hope students can master calculation more skillfully.
Write on the blackboard.
Practice class
Multiply half by 1/2.
The sixth grade mathematics first volume 1 unit courseware 4 teaching objectives:
1, master the reduction method in the process of fractional multiplication calculation, be able to perform fractional multiplication calculation correctly and skillfully, and improve students' calculation ability.
2. Cultivate students' reasoning ability and thinking flexibility in activities such as observation, migration, trial practice and exchange of feedback.
3. Create an open, democratic and interesting space for independent inquiry, encourage students to make bold guesses, and cultivate students' thinking quality of being brave in practice.
Teaching emphasis: master the simplification method in the process of fractional multiplication calculation.
Difficulties in teaching: mastering the fractional method of fractions skillfully and improving students' computing ability.
Teaching process:
First, check the import.
3/5×30 12×2/3 2/5× 1/3 7/8×3/4
When communicating, let the students say: (1) the reduction method of multiplying fractions by integers. ⑵ Calculation method of decimal multiplication.
2. Introduce new courses.
Today, in this class, we will continue to learn fractional multiplication.
Second, explore new knowledge.
1. Show examples.
Among invertebrates, squid swims fastest, with a speed of 9/ 10 km/min.
Solve the problem 1: Uncle Li's swimming speed is 4/45 of that of squid. How many kilometers does Uncle Li swim every minute?
(1) Reading comprehension.
Organize students to read the topic, understand the meaning of the topic, and draw the following conclusions:
The speed of squid is 9/ 10 km/min. Uncle Li's swimming speed is 4/45 of 9/ 10 km/min.
(2) Column solution.
Let the students answer independently according to their own calculation methods and communicate the solution process. The teacher answers the blackboard according to the students:
9/ 10×4/45=9×4/ 10×45=36/450=2/25
(3) Enlighten thinking.
When a fraction is multiplied by an integer, we divide the fraction first in the calculation process, which can make the calculation simple. Here, can we also make an appointment first? How to cut it?
Students think independently and try to calculate.
(4) exchange discussions.
The conclusion reached through communication is that the score is multiplied by the score. In order to simplify the calculation, the score can be reduced first and then multiplied. In division, two factors of the numerator and two factors of the denominator are divided.
3. Solve Question 2: How many kilometers can squid swim in 30 minutes?
(1) Students answer independently. The main points are as follows:
(2) Under the guidance of teachers, fractional multiplication can also be simplified directly.
Just try it.
How to reduce 9/ 10×4/45? Writing on the blackboard: (calculation process)
Important: Fractions can be multiplied by numerator and denominator.
5. summary.
Third, consolidate practice.
1. Title 1 on page 5 of the textbook.
Let students practice independently first, and then organize students to exchange reports, focusing on ways to share the main points when reporting.
2. "Do" on page 5 of the textbook.
Let the students read the topic first, understand the meaning of the topic, list the formulas according to the quantitative relationship of "speed × time = distance", then let the students calculate independently, and finally organize communication.
3. "Do" on page 5 of the textbook.
Students answer independently and organize exchanges to correct mistakes.
4. Question 6 of "Exercise 1" on page 6 of the textbook. Students answer independently and organize exchanges to correct mistakes.
Fourth, class summary.
Fractions can be multiplied by numerator and denominator.
Write on the blackboard.
Score times score.
9/10× 4/45 = 9× 4/10× 45 = 2/25 (km)
9/10× 30 = 9× 30/10 = 27km.
The sixth grade mathematics volume one unit courseware 5 teaching objectives:
1, through practice, further understand the meaning of multiplying a number by a fraction.
2. Through practice, further consolidate the calculation method of fractional multiplication and improve students' calculation ability.
3. Cultivate students' cooperative consciousness and good study habits in the learning process.
Teaching emphasis: master the calculation method of fractional multiplication skillfully.
Teaching difficulty: to cultivate students' ability to solve practical problems.
teaching process
First, check the import.
Review old knowledge.
(1) What does it mean to multiply a number by a fraction?
⑵ What is the calculation method of fractional multiplication?
4. Introduce new courses.
Today, in this class, let's do some exercises related to fractional multiplication! (blackboard writing topic)
Second, explore new knowledge.
1. Exercise on page 7, question 7 1.
This problem is a calculation exercise of fractional multiplication, which allows students to calculate independently before communicating. Remind students to observe whether they can cut back. If they can do subtraction, they can do subtraction first and then multiply. )
3. Show questions 8 to 1 3 in exercise1on page 7 of the textbook.
These six problems are common fractional multiplication problems in daily life, and a lot of extracurricular knowledge is designed in them. These exercises can not only deepen students' understanding of the meaning of multiplying a number by a fraction and consolidate the calculation method of fractional multiplication, but also expand students' knowledge, broaden their horizons and increase their knowledge.
In practice, students can read and understand the meaning of questions independently first, then answer them independently, and finally organize exchanges and reports.
Third, the class summarizes.
When calculating, you should master the calculation method and calculate accurately.
Write on the blackboard.
Fractional multiplication practice class
40× 1 1/20=22 (species)
Sixth grade mathematics book 1 unit courseware 6 first class
Teaching content: examples and "doing" on pages 2-3 of the textbook, and exercises 1 1~7.
Teaching goal: let students understand the position and express the position with several pairs.
1. In specific cases, explore the method of determining the position, and several pairs can be used to represent the position of the object.
Teaching emphasis: The position of an object can be represented by several pairs.
Difficulties in teaching: the position of objects can be expressed by number pairs, and the order of rows and columns can be correctly distinguished.
Teaching methods: lecture, demonstration, discussion and practice.
Teaching aid preparation: the teacher prepares multimedia.
Teaching process:
First, import
There are 54 students in our class. If I want to invite one of you to speak, can you help me figure out how to express it simply and accurately?
2. Students express their opinions and discuss how to use the method of "which column and which row".
Second, new funding.
1, teaching example 1
(1) If the teacher uses the second column and the third row to indicate the position of XX, can he also indicate the position of other students in this way?
(2) Students practice showing other students' positions in this way. (pay attention to the column first and then the emphasis of the lines)
(3) Teaching writing: the position of XX is in the second column and the third line, which we can express as: (2, 3). Can you write down your position according to this method? (Students write down their positions in their exercise books and name their answers)
2. Summary example 1:
(1) How much data did you use to locate a classmate? (2)
(2) We are used to saying columns before rows, so the first data represents columns and the second data represents rows. If the order of these two data is different, then the position of the representation is different.
Step 3 practice:
(1) The teacher reads the name of a classmate in the class, and the students write his exact position in the exercise book.
(2) When do you need to locate yourself in your life? Talk about the way they determine their position.
Third, practice.
1, Exercise 1, Question 4
(1) Students independently find out where the letters in the picture are and tell the answers.
(2) Students mark the positions of letters according to the given data, and connect them into figures in turn, and check them at the same table.
2. Exercise 1, Question 3: Guide the students to know how to read the page numbers first and find the corresponding positions according to the data.
Fourth, summary.
What did we learn today? What do you think of your present situation?
Verb (short for verb) homework
Exercise 1: Question 1, 2,5,7,8.
Six, teaching postscript:
By presenting the scene of determining students' seats in the multimedia classroom, students' existing life experience is used to lead out the study of this unit, which greatly mobilizes students' learning enthusiasm. Active guidance and guidance in teaching have deepened students' understanding of logarithmic pairs.
Second lesson
Teaching content: example 2, exercise 1, questions 3, 4, 6 and 7 on page 3 of the textbook.
Teaching objectives:
1. Through group cooperation and independent exploration and construction, students can determine the position with several pairs of combined grid paper, and can determine the position on the grid paper according to the given number of pairs.
2, through classroom learning activities, enhance students' ability to use what they have learned to solve practical problems and improve their awareness of application.
3. Through cooperative learning, demonstration and classroom interaction, let every student experience the happiness brought by learning and cultivate students' learning interest and learning ability.
Teaching emphasis: use number pairs to determine the position on square paper.
Teaching difficulties: correctly representing columns and rows with grid paper.
Teaching tool: a square paper map of the zoo schematic diagram.
teaching process
First, review the lead-in and put forward the learning objectives.
1, review: first, use a number pair to indicate a classmate's position in the class, and then say 1 number of the number pair. What does it mean? What does the second number mean?
2. Expose the topic and put forward the learning goal.
Let the students speak first, and then show their learning goals:
(1) Which lines represent columns and which lines represent rows on the grid paper?
(2) The method of using grid paper to determine the position of objects.
Second, show the learning results.
1, know the columns and rows of grid paper.
Vertical lines are columns and horizontal lines are rows.
2. Teach yourself and show in groups.
(1) Learn 3 pages of Example 2 independently, and complete 1 and 2 questions. These groups communicate and discuss with each other. Teachers use cameras to guide and collect students' learning information. The key point is to let students show different thinking methods and mistakes, especially to guide students to communicate and discuss in groups. )
(2) roll call students to perform.
3. Show it to the whole class.
(1) Question 1: The Panda Pavilion is in column 3, line 5, and is indicated by (3,5); The aquarium is in the fourth row of the sixth column, which is indicated by (6, 4); Monkey Mountain is in the second row of the second column, which is indicated by (2,2); The Elephant Pavilion is in the fourth row of the column 1, which is indicated by (1, 4).
(2) Question 2: Let the students in the board show how to mark the positions of various venues. For example, Bird House (1, 1) is located at the intersection of 1 column and 1 row. ...
Third, expand the extension of knowledge.
1. Finish the exercise 1, questions 3 and 4.
2. Complete question 6 of exercise 1.
(1) Write the position of each vertex on the graph independently.
(2) Vertex A is translated 5 units to the right. Where is it? Which number in the number pair has changed? Point a is further shifted upward by 5 units. Where is it? Which number in the number pair has also changed?
(3) Translate point B and point C according to the method of point A, and get a complete triangle after translation. Communicate and discuss with each other in groups. )
(4) Observe the pictures before and after translation and tell me what you found.
(5) Report: The graph remains unchanged. When moving to the right, the column changes, and the first digit of the digit pair changes. When moving up, the row changes, and the second digit of the digit pair changes.
(6) Students question, ask difficult questions and stimulate knowledge conflicts.
A. Students are free to ask questions and ask difficult questions in response to classmates' reports.
B. Teachers guide students with learning difficulties to ask questions: Students, have you encountered any difficulties in your study? Can you tell everyone about your difficulties? Then do you have any thoughts and suggestions on your classmate's statement?
Fourth, induction and summary.
What did we learn today? What do you think of your present situation?
Homework: Exercise 1, Questions 5 and 7.
Six, teaching postscript:
Through cooperative learning, demonstration and classroom interaction, let every student experience the happiness brought by learning and cultivate students' learning interest and learning ability.
The sixth grade mathematics first volume 1 unit courseware 7 teaching objectives:
1. Create a self-inquiry learning situation, so that students can understand the meaning of multiplying numbers by scores, master the calculation rules of multiplying scores by scores, and learn the simple calculation of multiplying scores by scores.
2. Cultivate students' ability of analogy and induction by organizing students to carry out mathematical activities such as migration, analogy, induction and communication.
3. Educate students to study purposefully and stimulate their learning motivation and interest through a widely used example of multiplying fractions by numbers.
Teaching emphasis: understand the meaning of multiplying number by score and master the calculation method of multiplying score by score.
Difficulties in teaching: deducing arithmetic and summarizing laws.
Teaching process:
First, import
1, calculate the following questions and tell the calculation method.
xxx
2. The above questions are all fractions multiplied by integers. Let's talk about the meaning of multiplying fractions by integers first.
3. Introduction: In this lesson, we will learn the meaning and calculation method of multiplying a number by a fraction.
Second, the new lesson
1, teaching example 3
(1) Show me the conditions and questions: Who painted this wall every hour, and what fraction of this wall is painted every hour? According to the formula "working efficiency × working time = total workload", the student formula is ×
(2) Guide students to operate, regard a piece of paper as a wall, draw the area of 1 hour in the first step, that is, the wall, and draw the area of hours in the second step, that is, draw the multiplication formula X for "how much?"
(3) x = is obtained according to the intuitive operation result, and the calculation method is deduced according to the operation process and result just now: x = =.
(4) Ask questions: How much do you draw per hour? Let the students color, deduce, calculate and solve problems independently by the previous methods.
2. Related exercises: Exercise 2, Question 5.
3. Summarize the significance and calculation method of multiplying a number by a fraction.
(1) Meaning: A number times a fraction, which means what the fraction of this number is.
(2) Calculation rules: the fraction is multiplied by the fraction, the numerator is multiplied by the numerator, and the denominator is multiplied by the denominator.
4. Teaching Example 4
(1) Guide students to analyze the meaning of the question according to the quantitative relationship of "speed × time = distance" and list the formula: ×.
(2) Let students calculate independently first, then exchange calculation methods, and make it clear that the score can be multiplied by the score first and then multiplied by it. By showing the students' calculation process, the writing format of reduction is further clarified: ()
(3) Students answer "How many kilometers do you fly in 5 minutes?" Another format of integer multiplying fraction is introduced in the notes.
5. Consolidation exercise: P 1 1 "doing" (pay attention to remind students to observe whether they can tangent before starting calculation).
Third, practice.
1, Exercise 3, Question 6
(1) How many decimeters are the two branches, that is, how many are the two branches? Formula: ×2
(2) Find the decimeter of a branch or branch length, which is sought or expected.
2. Exercise 3, Question 9. Students discuss and communicate, tell where the mistakes are, and explain them in combination with the mistakes that students are prone to make.
Fourth, homework
Exercise 2 Questions 3, 7, 8, 10.
The first volume of the sixth grade mathematics Unit 1 Courseware 8 I. Review.
1. What is the law of fractional division? (Name the students to answer)
2. Five times a number is 32. What's this number?
Ask students to list simple equations and tell their basis. )
Second, new funding.
1. Presentation topic: Computer presentation of text examples.
Teacher: What information can you get from this question? (Students answer and show)
Health: the water in adults accounts for about 2/3 of their body weight;
Water in children accounts for about 4/5 of their body weight.
Xiaoming has 28G of water in his body;
Xiaoming's weight is 7/ 15 of his father's weight.
(2) ask questions and solve problems.
The first question is how many kilograms does Xiao Ming weigh?
Teacher: What information can be used to solve these problems?
After searching, the students screened out useful information and arranged it into an application problem.
Water in children accounts for about 4/5 of their body weight. Xiaoming has 28 kilograms of water in his body. How many kilograms does Xiaoming weigh?
① quantitative relationship
What does a.4/5 mean?
B. Draw a line segment.