1, through comparison activities, master the method of comparing the sizes of numbers within 10,000, and be able to express the sizes of numbers within 10,000 with symbols.
2, through the estimation, combined with real materials, feel the significance of large numbers, and realize the practical role of estimation in real life.
Teaching preparation:
Teacher: Digital card,
Student: Digital cards within 100.
Teaching process:
First, review.
1, use digital cards within 100 at the same table, and each person will draw one at a time. Whoever says the big number first wins.
2. Exchange experience in judging large numbers.
Second, new funding.
1, teach "comparison"
(1) Let me see 1084 and 982. Tell me who is older and who is younger.
(2) Students said: Three digits are less than four digits, so1084 > 982
(3) The teacher shows some other figures and the students compare them.
(4) summarize the law:
Digital comparison:
(1) The more digits, the greater the number.
(2) Compared with bits, the number of bits is larger (the number of bits is the same)
(3) If the number of digits is the same as the number of digits, let's compare the next digit.
2. practice.
(1) Students complete P36, fill in O, =
(2) Tell me why you filled in this way.
Step 3 give it a try
(1) Teachers guide students to read the questions and understand their meanings.
(2) Tell me how to compare sizes quickly.
(3) Teacher's summary:
Divide these numbers by digits first, and then compare them with the same number.
99 & lt345 & lt387 & lt809 & lt 1725<4300
Step 4 think about it
(1) Guide reading and understand the meaning of the question.
(2) The smallest four digits are 1000 and the smallest four digits are 9999.
5, math games:
(1) Tell your deskmate what number you wrote. ...
(2) Ask a student to give a demonstration on stage, and then the whole class will do it in groups.
6. practice.
Complete exercises 1 and 2.
Three. abstract
What did the students learn in this class?
1, learned to compare the sizes of numbers within 10,000.
2. How to compare four digits with three digits?
3. How to compare numbers with the same number?
4. How to compare many numbers together?
Fourth, homework
1, the smallest four digits are (), and the four digits of are ().
2. The smallest three digits are (), and the three digits of are ().
3.287,7650,80,285, 165 1 79 Among these figures, two digits have (), three digits have () and four digits have ().
4、427 O 527 1620 O 620 888 O 988
29 O 1 10 99 O 999 6080 O 3090
Chapter II Teaching Objectives:
1, through comparison activities, master the method of comparing the sizes of numbers within 10,000, and use symbols to represent the sizes of numbers within 10,000.
2. Cultivate students' inductive ability and oral expression ability.
3, through various forms of activities, combined with real materials, feel the meaning of large numbers.
Teaching focus:
Comparison method of number size within 10 thousand
Teaching difficulties:
Let the students sum up and master and use the method of comparing sizes skillfully.
Teaching process:
First, create situations and introduce new lessons.
Our motherland has beautiful scenery and rich products. Famous mountains and great rivers fascinate the world. Today, the teacher will lead us to several beautiful scenic spots and learn some math knowledge while enjoying the beautiful scenery.
Second, (show the scene map).
1, observe the situation map and look for mathematical information.
2. Put forward valuable mathematical problems according to the situation diagram.
(1) Who? Who is the lowest?
(2) Who is taller than Huangshan and who is taller than Mount Tai?
(3) Compared with Huashan Mountain, which mountain is higher?
Third, autonomous learning.
Choose one or two questions according to the questions raised and discuss them in groups.
Fourth, report the learning situation.
Blackboard writing: the direct proportion of different numbers
Same number of digits, more than the first digit.
The first place is the same, in turn than.
Can you fill in the list from small to large?
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