The content of "division with remainder" is the extension and expansion of division knowledge in the table. This textbook is divided into two parts. The first part is the significance and calculation teaching of remainder division, including theme map and three examples. The other part is problem solving, which is Example 4. First of all, the textbook provides students with the material for division calculation through the situation of extracurricular activities in the theme map, strengthens the comparison between divisibility and division with remainder, and communicates the connection between knowledge.
Teaching objectives:
1. Let students understand the meaning of divisibility.
2. Master the relationship between the parts.
3. Cultivate students' ability of analysis, judgment, logical reasoning and solving practical problems.
Teaching focus:
Understand the meaning of divisibility and further understand the relationship between the parts.
Teaching difficulties:
Let the students understand why the remainder is less than the divisor.
Prepare teaching AIDS and learning tools
Cards, projectors, slides.
Teaching step
Pave the way for pregnancy
1. What is the relationship between the parts of the review class?
2. Show me the card: (If you can calculate orally, you must calculate verbally)
24÷3= 25÷3= 38÷2=
180÷ 12= 39÷2= 184÷ 12=
3. Introduction: From the review just now, we can see that the students have mastered the meaning of division and the relationship between multiplication and division. So today we continue to study. (Title on the blackboard:) Show the demo courseware and download the title.
(2) Explore new knowledge
1. The concept of teaching separability:
(1) The teacher showed the division formula in the dictation card just now.
24÷3=8 25÷3=8…… 1 38÷2= 19
180÷ 12= 15 39÷2= 19…… 1 184÷ 12= 15……4
Teacher's question: Can you classify the above six division formulas according to the number of points in each question?
Before naming, rearrange the six formulas as required.
①24÷3=8 ②25÷3=8…… 1
38÷2= 19 39÷2= 19…… 1
180÷ 12= 15 184÷ 12= 15……4
The demonstration courseware ""shows two sets of formulas for download.
Student discussion: what is the basis for this classification?
Let the students understand that the numbers are arranged according to whether there is a remainder or not.
(2) Teachers guide students to observe the first group of questions.
The teacher asked: What are the dividend, divisor and quotient of this group of questions? Can you give a few more examples?
Teacher's summary: Just now, the students listed that the dividend is an integer, the divisor is an integer that is not 0, and the quotient is also an integer, but no, we call this division divisible. Under this condition, we say that the first integer can be divisible by the second integer. For example, 24 ÷ 3 = 8, we say that 24 can be divisible by 3, or it can be.
Guide students to try to sit at the same table and say: Formula 38 ÷ 2 = 19 and 180 ÷ 12 = 15, who can be divisible by whom.
(3) Feedback exercise: 72 pages of "Do it", displayed by projection (students explain the reasons when judging)
Which of the following divisions can divide the first number by the second number?
16÷3 48÷6 80÷ 16 9 1÷ 17
2. Teaching:
(1) Teachers instruct students to observe the second set of formulas:
Teacher's question: Observe the second group of questions. What are the characteristics of dividend-divisor = quotient in these formulas?
After the students answered, the teacher summed up the concept: like this group of division questions, all are integers divided by another integer that is not 0, and the quotient obtained is an integer with a remainder. This division is called division.
(The courseware ""shows the definition of remainder division) Download.
Feedback exercise: Show the following questions: (Projection)
13÷2=6…… 1 38÷ 19=2
49÷5=9……4 26÷3=8……2
The teacher asked: which of the above four division formulas is it? What's the name of 38÷ 19 = 2?
Guide the students to observe: What are the characteristics of the remainder in the book?
For example, the teacher, students judge right or wrong:
19÷6=2……7 19÷6=3…… 1
Let the students understand that the remainder is less than the divisor. The teacher can trace the remainder of the second set of formulas on the blackboard with colored chalk. )
(2) Teaching the relationship between the parts of remainder division.
The teacher showed:
25÷3=8…… 1 184÷ 12= 15……4
Guide the students to say: What are the dividend, divisor, quotient and remainder in the formula?
Let the students observe first and then think: how to find the dividend in the above division formula.
Inspire students to answer:
3× 8+1= 2512×15+4 =184 (the teacher corresponds to each formula on the blackboard).
Teacher's summary: Dividend = quotient × divisor+remainder (blackboard writing) Continue to download demonstration courseware.
(3) Feedback exercise: "Do it" on page 72, using projection to show:
Please check whether the following division calculation is correct. (Projection display)
367÷23= 15……22
When reviewing, let the students talk about what the foundation is.
(3) Consolidate development (forecast)
Group a:
1. Fill in the blanks:
(1) When a number is divided by another number, the quotient is and there is no remainder, we say that the first number can be divided by the second number.
(2) 28 ÷ 14 = 2 is divisible.
(3) When one is divided by another, the chamber of commerce will be later. This division is called, all are smaller than divisor.
(4) Divider _ _ _ _ _ _ × _ _ _+remainder.
2. Choice: Draw a horizontal line under the divisible formula.
( 1) 124÷3= (2)45÷9=
(3)72÷9= (4)52÷4=
3. Calculate the following questions and check them.
9350÷46
4. Exercise 16, question 3.
Fill in the missing figures in the table below.
divisor
divisor
business
residue
175
23
18
2 1
five
478
13
10
5. Exercise 16, question 5.
How many numbers are divisible by 3 within 20? Add up these figures, can they be divisible by 3? how much is it? Colour numbers that are not divisible by 3.
1
2
three
four
five
six
seven
eight
nine
10
1 1
12
13
14
15
16
17
18
19
20
Group b:
1. Surrounding space:
(1) is divisible by 126 ÷ 3 = 42.
(2) If A ÷ 8 = 4, it is divisible.
(3)a and B are integers, and b≠0. If a ÷ b = 5, it can be divisible.
Please connect the numbers in the first line with those in the second line.
48 70 9 1 100
2 3 5 7
3. Calculate the following questions and check them.
1320÷35
4. Exercise 16, question 3.
Fill in the missing figures in the table below.
divisor
divisor
business
residue
175
23
18
2 1
five
478
13
10
5. Exercise 16, question 5.
How many numbers are divisible by 3 within 20? Add up these figures, can they be divisible by 3? how much is it? Colour numbers that are not divisible by 3.
1
2
three
four
five
six
seven
eight
nine
10
1 1
12
13
14
15
16
17
18
19
20
Group c:
1. Judgment: draw "√" on the right and "×" on the wrong.
(1) In 23÷6, the first number cannot be divisible by the second number.
(2)480÷25= 19…… 15.
(3) The remainder must be less than the divisor.
(4) Only divisible by 7.
360 is divisible by 2, 3 and 5.
2. Calculate the following questions and test them.
36900÷2 10
3. Sporting goods factory should pack 4000 badminton, each tube 12. How many badminton can these badminton hold at most? How much is left?
4. Exercise 16, question 3.
Fill in the missing figures in the table below.
divisor
divisor
business
residue
175
23
18
2 1
five
478
13
10
5. Exercise 16, question 5.
How many numbers are divisible by 3 within 20? Add up these figures, can they be divisible by 3? how much is it? Colour numbers that are not divisible by 3.
1
2
three
four
five
six
seven
eight
nine
10
1 1
12
13
14
15
16
17
18
19
20
(4) class summary
Teachers and students * * * sum up, what is divisibility, what is division with remainder and the names of each part, and how to check division with remainder.
(5) Transfer
1. Fill in the formula on the specified horizontal line as required.
324÷4= 52÷8= 40÷3= 72÷9= 120÷ 10=
Separable equation is _ _ _ _ _ _ _ _; The inseparable formula is _ _ _ _ _ _ _.
2. Exercise 16, question 4.
Sporting goods factory has 4000 shuttlecocks to be packed, each tube 12 shuttlecocks. How many badminton can these badminton hold at most? How much is left?
3. Exercise 16, question 6.
At the beginning of the new term, Miss Li bought 250 exercise books for the students. After distributing it to 40 students in the class on average, there are still 10 books left. How many exercise books were distributed to each student on average?