There are numbers in the box. As can be seen from the following equal sign, because Xiaoxue's first grade can only be a problem of addition and subtraction, that is to say, three numbers are added and subtracted to get a result. After reading the picture, the boxes in the picture are grouped by balls.
example
A=5 equation.
2+3=5 equation.
2+3=a+b=6+c equation.
2+5≠ 10 inequality.