Teaching objectives

1. Learn how to add a few digits to 5, 4, 3 and 2, and master the calculation method of "using oral decimals to increase numbers, you can use large corner decimals".

2. Cultivate students' reasoning ability and thinking flexibility. The key and difficult point is to master the method of "thinking about big corner decimals" and increase the decimal places orally. Teaching AIDS, dictation cards, video projections, etc.

teaching process

1, display: 5+7= (), think about it, how to calculate? Try to calculate and write the result.

2. Report. Students report and the teacher writes on the blackboard: Thinking: 5+7= () Look at the blackboard for discussion. How to say the numbers quickly? The teacher stressed: these methods are all right, but when calculating decimal multiplication, we usually adopt the method of "exchanging decimal places with large numbers and thinking about large decimal places", which is faster.

3. Trial teaching method calculation: 5+8= (). Independent calculation. Talk to each other. Ask one or two students to talk about this process. For example, let's talk about how to calculate first. Done independently. Students report the revision and give the students with questions an opportunity to explain the process consolidation method.

4. Summarize and reveal the topic. Today, we learned the addition of 5, 4, 3 and 2. Do you know how to calculate the number that can be calculated quickly? You say it yourself.

abstract

Analysis of teaching materials and learning situation The focus of this lesson is to let students explore the calculation method of 5, 4, 3 and 2 plus several by themselves through practical exploration and cooperation. Students have a certain foundation in calculating this part, so they can master it mainly through their own exploration.

The addition in this lesson is basically a small number plus a large number, so that students can use their favorite methods to calculate, especially in addition to the "ten-complement method", they can also directly calculate the numbers by contacting the corresponding addition formulas they have learned, encouraging the diversification of algorithms.

Pay attention to the comparison between formulas, realize the connection between knowledge, facilitate the migration of algorithms, then sort out and solve practical problems, and guide students to consolidate and apply what they have learned.

The classroom design shows that the content of this lesson is based on students' learning "9, 8, 7, 6 plus a few". Because students have a certain knowledge base, we should boldly let students solve related mathematical problems through analogy and migration in teaching design.

At the same time, teachers should also pay attention to the role of comments in the process of students' autonomous learning, so that students' autonomous learning can be hierarchical and deep, and good teaching results can be achieved.