1
Teacher: Introduce stories and reveal topics.
Students, have you heard the story of two generations of love? There is one here today.
The mathematical story of "Grandpa divided the land",
do you want to hear it ?
(courseware shows pictures)
Who wants to tell this story to everyone? Read a story by name
Be as emotional as possible.
Grounding)
Story:
An old man wanted to give a piece of land to his three sons.
The boss got the land,
The second child was assigned to this land.
about
, the old three points to this piece. The boss and the second thought they were suffering, so the three men quarreled. Just right, Fan.
Passing by asked the reason for the quarrel, laughed and said a few words to them, and the three brothers stopped quarreling.
2
Teacher: Do you know why two generations of love laugh? What did he say to the three brothers?
three
Students can speak freely after guessing.
four
Students have so many ideas! How did the clever two generations of love make the three brothers stop quarreling?
(2) Explore new knowledge and solve problems.
1
、
Hands-on operation and image perception
(
1
) Do the three brothers really share the same amount of land? Can you prove it in your own way?
(
2
) Students independently operate and verify.
way
1
Methods of drawing, drawing, folding and drawing
way
2
The calculation method.
way
three
Invariance of quotient.
(
three
) Observe and tell me what you find.
2
Show and do (
1
)
(
1
) Please observe carefully. Tell your deskmates what the colored parts of these three figures mean.
Show me the score.
(
three
) Observe and tell me what you find.
= =
(courseware revealed)
(
four
) communication: what else did you find?
The numerator and denominator of the fraction have changed, but the size of the fraction has not changed.
The numerator and denominator of a fraction are multiplied by the same number, and the size of the fraction remains the same.
(blackboard writing: multiply all by
The same number) (courseware demonstration)
three
Show and make pictures (
2
), students fill in the scores independently.
(
1
) What do you think?
(
2
)
Communication,
What did you find?
(The numerator and denominator of a fraction are divided by the same number,
The size of the score remains the same.
)
(cardboard
Book: divide all by
The same number)
six
Think about it: the basic nature of inductive fractions
(
1
What did you find from the demonstration just now?
Blackboard writing: both the numerator and denominator of a fraction are multiplied or divided by the same number, and the size of the fraction remains the same.
(
2
) The basic nature of supplementary marks: The courseware shows two formulas and asks the students if they are right. Explain the keyword "Du",
"same number"
Except ".
What word can be used to mean "Du"? -"At the same time."
Blackboard writing: The numerator and denominator of a fraction are multiplied or divided by the same number (
Except), the size of the score remains unchanged.
(
three
Exposed topic: the basic nature of scores. Ask the students to find out the key words in the basic nature of music score in the textbook and take notes.
Numbers (pictures or circles) require the key words to be stressed. (courseware revealed)
seven
Knowledge sorting and communication: what are the basic properties of the scores related to what you have learned? Can you give an example? Teacher:
We studied the relationship between fraction and division,
Know that fractions can be written as division.
Now let's put the invariance of quotient,
minute
What do you find by connecting the basic properties of numbers with the relationship between fractions and division? (Example verification, such as:
3/4
=
three
÷
four
=(
three
×
three
)÷(
four
×
three
)=
nine
÷
12
=
9/ 12
) (courseware revealed)
Teacher:
In fact,
There are many places in mathematical knowledge, such as the invariable nature of quotient and the basic nature of fraction.
classmate