1. According to the four known numbers, a circle, a square and a triangle represent three numbers respectively. The position of two numbers in each picture represents a certain addition and subtraction relationship.

2. Further analysis shows that square = 1, circle =2 and triangle =5.

When the number outside is smaller than the number inside, the two numbers are added. As shown in the first picture: 1+2=3. When the number represented by the external number is greater than the number represented by the internal number, the small number is subtracted from the large number. As shown in the second figure: 2- 1= 1.

According to the above rules, the result of the last figure is the addition and subtraction of triangles and circles. Because a triangle is bigger than a circle, the result is 5-2=3.

A little wordy, I hope it will help you ~ ~ ~