how much does a smart board weigh.In the same way, the addition and subtraction teaching of numbers can also make the knowledge intuitive and image. For example, first-year students learn subtraction . In the " solving problem " teaching , I used multimedia whiteboard to design such a shopping activity : Mom gave Xiaohong 5 yuan , let him go to the street to buy snacks , and ask students to think about it . If you are Xiaohong , how would you buy it? In the courseware , just click on the favorite snack , the waiter will bring the snacks up. This is an open question and a familiar activity for students . Students' thinking will not be framed. They can make a variety of choices based on the variety of snacks provided and their individual requirements , combined with the "5 yuan " condition , to develop different purchase plans. Such a learning process , not only active in the classroom atmosphere , increasing the participation of students face , but also improves the ability of students to independently solve problems.