1, application in real life. Through estimating activities and combining with real materials, let students feel the significance of large numbers and realize the existence of estimation.

2. Understand the strategy of estimation and cultivate students' awareness and ability of estimation.

Teaching focus:

Understand the strategy of estimation and cultivate students' awareness and ability of estimation.

Teaching difficulties:

Estimate according to the actual situation.

Teaching preparation:

courseware

Teaching process:

First, situational introduction

Students, do you like reading stories? Today, the teacher brought you a short story. Please have a look. Students can read short stories freely.

Show courseware: Who is the hero of the short story? What do you think of him?

Students think and answer.

Extension: Do you want to be such a person? If you want to be such a person, then you must love reading and study hard. Only when you grow up can you realize your wish.

(Design intention: With the help of short stories, enlighten and educate students to love reading and study hard. )

Second, independent inquiry.

1. The short story we just read is not too long. Do you know how many words there are? In this lesson, we will learn how many words there are together. (blackboard writing topic)

Courseware presentation problem: In real life, we only need a rough data, or we can't make detailed statistics. What should we do? Students discuss and report their ideas.

Conclusion: In order to solve these problems, we need to learn how to estimate.

Now, please estimate. How many words do you think there are in this short story we just read?

Students report the estimated results.

Conclusion: Estimation is not a wild guess, but also needs to pay attention to methods and strategies.

Our estimates just now are too different. Now please discuss it and tell us how to estimate it accurately. Students discuss and communicate, and teachers patrol and guide.

Students report the results of the discussion.

1, each line has about 10 words. A few lines in each paragraph can estimate the number of words in each paragraph, and finally the number of words in the whole story can be estimated.

2. According to the calculation of about 10 words per line, it is estimated that there are about 50 words in the right column and about 100 words in the left column, so the whole story is about 150 words.

2. (Courseware shows page 30 of the textbook. Evaluate and fill in. )

Show me this question: Can you estimate how many soybeans are in the cup? Speak your mind.

Students discuss and report.

(Design intention: Use concrete examples to guide students to learn estimation methods and cultivate estimation skills. )

Third, consolidate the practice.

1, 3 1 Page 2 Comparison and estimation.

2.3 1 page, estimated 3 questions. How many jelly beans are there?

Fourth, class summary.

How do you think we should estimate? Student report.

Verb (abbreviation for verb) homework after class

Page 3 1, 1, how many words are there?