The knowledge point of "understanding numbers within 100" in senior one and senior one mathematics.
1, from the right, the first digit is one, the second digit is ten, and the third digit is one hundred. Reading and writing methods: both reading and writing should start from the high position.
2. Singular number: a natural number with the unit of 1, 3,5,7,9.
3. Even numbers: natural numbers with units of 0, 2, 4, 6 and 8 (except 0).
4. Integer: a natural number with the unit of 0 (except 0).
Five tens and five ones make fifty-five. (Five decimal places means five tens, and five decimal places means five ones. )
Reading: 55 (writing Chinese characters) Writing: 55 (writing mathematical characters)
6, 10 one is ten, 10 ten is one hundred. (One, ten and hundred are counting units. Write Chinese characters)
Composition of numbers: (Pay attention to different ways of asking questions)
Example: 68 consists of 6 tens and 8 ones; 68 consists of 8 1 and 6 10.
There are (6) tens and (8) ones, and (68) ones.
The decimal digit is 6, which means 6 tens (writing Chinese characters), and the unit digit is 8, which means 8 ones (writing Chinese characters).
7. The method of comparing the size of two digits: look at the ten digits first, and the bigger the number, the bigger it will be. If the ten digits are the same, if you look at one digit, it will be bigger. (The opening faces a large number and the tip faces a decimal number. )
8. When the difference between the two quantities is large, it can be described as "much more, much less"; When there is little difference between the two quantities, it can be described as "more, less".
2 1 Grade Mathematics Teaching Plan "Understanding Numbers within 100"
Teaching objective: 1. Can correctly count the number of objects within 100 in different ways, and know that these numbers are composed of ten and one. Feel the number 100, establish the concept of number, initially know the counting unit of one, ten and hundred, and know that 10 is ten and 10 is hundred.
2. Through the process of abstracting numbers within 100 from daily life, I learned the counting method, realized that the principle of counting is decimal counting, and felt the meaning of numbers within 100 by estimating the number of objects within 100.
3. Let students experience the fun of cooperation and communication in activities, and express and communicate with the number of expressions in life. Cultivate students' feeling, interest and consciousness of counting.
Second, the difficulties in teaching:
Teaching emphasis: master the numbers within 100 and the composition of numbers, and establish the sense of numbers within 100.
Teaching difficulty: in the process of counting, the number of turns (turns) is close to the whole ten.
Third, teaching preparation:
Courseware, sticks, lucky stars, peanuts, claws
Fourth, the teaching process:
(A) to create an environment to stimulate interest
Teaching theme map:
1, (courseware shows dynamic theme map 10 lambs): A group of lovely lambs came up on the beautiful prairie. Do you know how many lambs there are? Let's count. See who can count as fast as a dot.
2. Student Count (1- 10)
3. Teacher: What's your date? (One by one) Is there any way for everyone to see at a glance that it is 10 sheep? (courseware demonstration 10 only takes one lap)
Teacher: How many 10 are there? (10 one) That is to say, 10 one is ten.
Teacher: 10 is that all? Look, here comes another group. How many sheep are there now? Let's keep counting! How many tens are there in (1 1-20)20? (20) So much is 20!
【 Design Intention 】 Through the intimate material of counting sheep, we can understand the starting point of students' learning, review and feel the methods of counting sheep one by one, and know how many are 10 and 20, so that students can know that counting sheep should be one-to-one, and their hands and mouths are consistent.
4. (The courseware shows 100 sheep walking) Look, there are so many sheep on the grassland. How many are there now? (Student assessment)
5. Teacher: Everyone's estimate is more than 20. Today, we will learn more than 20 numbers and the composition of numbers.
【 Design Intention 】 On the basis that students have already felt the actual number of 20, it is not only beneficial to cultivate students' sense of number and estimation ability, but also beneficial to students to experience the estimation method.
(2) Operation and query
1, teaching example 1
Teacher: How many sheep are there? Today, the teacher prepared as many items as the number of lambs for each group, so we will count them together, not the number of lambs, to see which group counts correctly and accurately. And let everyone know at a glance.
② Students count items in groups.
③ Report and exchange: How many did your group count? How do you calculate it? Take a number of places one by one, in groups of ten, and let me show you. )
【 Design Intention 】 The number of lambs was replaced by school tools, which permeated the mathematical thought of mathematical symbols. Through group cooperation, the number is less than 100, so as to create a space for students to build their own knowledge, pay attention to the subjective initiative of each student, respect the potential of students' nature, allow them to count 100 projects in different ways, and pay attention to their personality differences.
Teacher: Just now, the result of your counting is different. The teacher also prepared as many sticks as the lambs. Let me count.
(The teacher shows 43 sticks) Do you know how many sticks the teacher has counted now? Let's count down together!
⑥ Boot counting: First count from 43 to 49 one by one. When counting to 50, ask: What is 1 after 49? How did you know? (Demonstrate the process of binding 10 pieces) and then count them one by one from 5 1-59. When you count to 60, ask: What's the number after 59? how do you know (Demonstrate the process of 10 binding again. ) When you count to 62, add them in bundles. Ask the students to count from 1 10 to 92. Finally, when counting from 92 to 99, ask: What's the number after 99? Tell everyone what you think!
⑦ Teacher: It turns out that 100 is so much. Let's count it again (1 10 places). How many tens are there in 100? Blackboard: 10 Ten is 100.
【 Design Intention 】 By purposefully guiding counting, students can experience the number series within 100 and know the diversity of counting methods. Demonstrate the process of tying 10 sticks into a bundle, so that students can understand that the principle of counting is decimal counting method, know that 10 is one hundred, and establish the counting unit of numbers; Think about what the last number is, so that students can solve the teaching difficulty of counting the whole ten hours through their own independent thinking on the basis of intuitive understanding, and fully feel what 100 is.
⑧ Count 100 sheep.
Teacher: 100 sticks replace the number of lambs. Did you count correctly? I hope that when you count, you must take one, count one, and take it as fast as counting!
Can this 100 sheep be seen at a glance? Do you have any good ideas? (Every 10 turn) Count again 1 10 times.
Pet-name ruby summary tip topic: Today's figures are all within 100. It seems that the numbers within 100 can be not only one by one, but also ten by one.
【 Design Intention 】 It is further understood that 10 is 100, and the number within 100 can be not only 1, but also 10 times 10.
2. Teaching Example 2
Count from 35 to 42.
Teacher: Counting is really interesting! Now count from thirty-five to forty-two.
(Courseware demonstration) When the students count to forty one by one, the courseware demonstration is full of ten bundles, and the last number after 39 is 40.
② Counting exercise (driving a train)
A, and then count from 38 to 50;
Count from sixty-eight to one hundred.
【 Design Intention 】 With the help of multimedia demonstration, students can intuitively strengthen their memory of the number of laps, and then use interesting train games to train them to count from concrete to abstract. It embodies its hierarchy, and at the same time expands the scope of counting, so as to achieve the purpose of everyone participating in learning activities.
3. Teaching Example 3
(1) The teacher takes out fifty-two sticks (students close their eyes) to see who can see how many at a glance. (blackboard writing: 35)
How did you know it was fifty-two? () Ten and () One (Show after students answer)
③ To put it completely, there are (5) tens and (2) ones in fifty-two miles.
④ Exercise: (Show P33 and do it)
Figure 1 feedback:
A. How do you know there are some pens in the picture? One box at a time.
B and 46 have () ten and () one.
Figure 2 Feedback:
A, this is () a ten, () a one.
B, (2) ten and (4) one ()
[Design Intention] Let students observe freely, let students express their ideas orally, and cultivate their ability of observation and expression.
(3) Practice and sublimation
1, 100 ball diagram demonstration: how many balls are estimated first? Then let the students exchange counting methods, demonstrate different counting methods, and finally choose a fast and convenient counting method.
【 Design Intention 】 The courseware shows 100 balls in disorder, which allows students to estimate and cultivate their estimation consciousness. Then, show the sorting chart of 100 balls, and let students exchange counting methods, so that students can have a variety of counting methods. Finally, they can choose their favorite counting methods by comparison and improve their skills in choosing the appropriate counting methods.
2. Fill in the blanks:
Answer, 56, (), (), (), (), (), ()
b、()、()、80 、()、()
[Design Intention] Give out the last five numbers of 56 completely, in order to let students go through the series and turns. Expanding exercise is to apply the counting method learned today and master it.
3. Numbers in life
Today, we learned the understanding of numbers within 100. We know that dozens are a hundred, and we also know that dozens have dozens and dozens have several ones. In fact, these numbers are everywhere in our lives. For example, the 8 1 bus and the 82 bus we saw today. We spent 40 minutes in this class. Have you seen these figures anywhere?
Reflections on the Teaching of Mathematics "Cognition of Numbers within 100" in Senior Three and Senior One.
First, pay attention to situational introduction and combine mathematics with real life. I consciously chose some living materials to provide children with interesting math problems, such as counting wisdom stars, counting peanut seeds for farmers' uncles, and citing numbers within 100 in life. Let students realize that there are many math problems in life and feel close to math knowledge.
Second, the role of teachers and students has changed, allowing students to be independent, cooperative and inquiry, and the classroom has become a press conference for students' research results.
German educator Froebel said: children have strong driving force and creativity, and the task of teachers is to manage and guide them. Give play to their motivation and creativity in meaningful activities. This lesson fully stimulates students' initiative in learning and the spirit of exploration and research by competing for wisdom stars, estimating the number of sheep, cooperating in groups to count seeds, choosing their favorite school tools, grouping free relay numbers, guessing games with each other, and finding numbers within 100 in life. Especially when reporting the method of group cooperation within 100 people, it is a small press conference of students' research results.
Third, timely evaluation, let students feel the joy of success.
In every link of this lesson, when students use the mathematics knowledge they have learned (counting seeds in groups and giving life examples) to complete a task of exploring knowledge (counting methods) or solve a problem, teachers enthusiastically give affirmation and encouragement, and award them with the star of wisdom, so that students can achieve success and happiness.