2. First of all, from the decomposition of 2, let children count the number of things with two identical things, and then separate them. Children can clearly and intuitively see that two things can be divided into 1 and 1, which means that 2 can be decomposed into 1 and 1, and then tell them 1 and 60/in turn. Putting it out in kind can better help children understand.
3. Next is 3. Similarly, take out three items, put one on one side and the rest on the other, and you can intuitively see one on one side and two on the other. So 3 can be decomposed into 1 and 2, and 1 and 2 form 3, 1+2=3. Inverted 3 is first broken down into two, and then the rest is put on the other side, which is the second decomposition method of 3. 3 can also be decomposed into 2 and 1, 2 and 1 to form 3,2+1= 3.
4. Each number can be decomposed into one less than its own number, which means that 2 has one decomposition, 3 has two decomposition methods, 4 has three decomposition methods, 5 has four decomposition methods, and so on. Next, we break down the number 4. First, we put one on the left and the rest on the right. It's not difficult to count three on the right. 4 can be decomposed into 1 and 3, and then we take one from the right and put it on the left, which is the second decomposition of 4. We see that there are many faces at this time. 4 can be divided into 2 and 2, and the third is to take one from the right and put it on the left. At this time, we can see that 4 can be decomposed into 3 and 3. At this time, we summed up a rule. Each number starts from 1 on the left and the remaining numbers on the right. Then we take one from the right and put it on the left at a time.