1, do you have any other formulation methods? Guide the students to find that if the fourth fish tank is also regarded as having four goldfish, you can list the multiplication formula. )

Write on the blackboard according to the students' answers: 4× 4-2.

Q: What does 4×4 mean? Why subtract 2?

2, induction

Equations like 4×3+2 have multiplication and addition. We call it multiplication and addition, and 4× 4-2 has multiplication and subtraction. We call it multiplication and subtraction. Can you look at these two equations and talk about what counts first? What is it?

Teacher: In a formula, there are multiplication and addition, or multiplication and subtraction. You should calculate multiplication first, then add or subtract.

3, guide to complete the "try"

Let the students calculate separately first, and then name the algorithm.

4. Question: After studying the last two questions, what do you think should be counted first if there are multiplication and addition in a formula?

5. Application

Textbook page 12, questions 1, 3 and 4.

Question 1, how did you formulate it? 3×4+ 1= 13

Question 3, question on the left 1 * * * How many people are there? How to form?