What if one piece of notation is missing in the Olympic Games?

What if one piece is missing from the Olympic notation? In fact, there are two common solutions to this kind of problem:

One is to directly calculate the number of missing blocks, and the other is to calculate the number of missing blocks by subtracting the number of good blocks from the total number of blocks. The two calculation methods can check each other. Various methods can be used to reach the correct conclusion. You can draw a picture, or measure and estimate with your fingers, and get the number of missing blocks.

This type of problem-solving thinking is good for children to improve their mathematical thinking and expand their methods, and it is also a good material. Give it to children. Just look more.