This practical activity is a mathematical activity of playing poker. Students should choose an operation method according to the numbers on three or four cards to calculate 24. The textbook arranges activities in three parts. First of all, through learning one, guide students to calculate the method of 24 according to the numbers on the card; Secondly, let students explore the method of calculating 24 according to the given four cards through "try it"; Finally, arrange a "comparison", let the students touch the card and work in groups of four to see who can work out 24 first.

This practical activity class can strengthen oral practice of addition, subtraction, multiplication and division, stimulate students' awareness and strategies of actively exploring and solving problems, and stimulate students' interest in learning.

Analysis of learning situation

1 In the process of "learning one thing", students combine playing cards with mathematics through the method and operation steps of "Counting 24 points" game, and organically combine various operations of addition, subtraction, multiplication and division, and then have a small challenge and star competition, so that students can "play" in an organized, purposeful, orderly and fun way.

2. Feel the diversity of algorithms. There is often only one way to calculate 24 points with three cards, but there may be many ways to calculate 24 points with four cards. (Sometimes three cards and four cards don't necessarily count. Therefore, it is not the only way to guide students to combine estimation, try various calculation methods, cultivate the flexibility of thinking and realize problem solving in teaching. The whole classroom atmosphere is ok.

Teaching objectives

1. Master the basic method of calculating 24 points, and further improve the oral calculation ability in the practice of addition, subtraction, multiplication and division.

2. Know that different cards can be counted as 24, and the same card can be counted as 24 points in different ways, thus improving the strategy and ability to solve problems.

3. Enhance students' interest in learning mathematics, and further cultivate students' sense of competition, cooperation and exploration.

Teaching emphases and difficulties

Key points: Understand and master the calculation methods and rules of 24 points, and be able to quickly calculate 24 points with three cards.

Difficulty: 24 points with 4 cards.