The teaching goal (1) is to make students better master analytical thinking and problem-solving methods by comparing one application problem with another. (2) Cultivate students' analytical and reasoning abilities. Teaching emphasis and difficulty: through analysis, find out the similarities and differences between the two application problems. Difficulty: Understanding that both application problems are calculated by subtraction, but their meanings are different. Teaching process design (1) review preparation 1. Do oral calculations. (By train) 26+30 27-9 40-4 37+10 60-40 38+6 56+4 40+28 (2) Draw a picture to count as one. The first line of the picture:-.