The question of how much to compare in grade two is relatively simple. In fact, to solve such an application problem, it is mainly to consider which one is needed, which is the key to distinguish. Many people think that who uses addition is less than who uses subtraction when they see who is more than who, which is a wrong concept in itself. When you do the problem, you should carefully interpret the relationship.

For example, given that A is 15 and A is more than B 15, what is B? To do such a problem, in fact, we put the required data in front to find B, so it must be greater than or less than A. It is known that A is greater than B 15, then conversely, B is smaller than A 15, then B =15 = 0.

If the topic is changed to known A is 15, and B is more than A 15, what is B when doing this topic? B, the unknown has been put in front, we can directly think that B is more than A 15, then B is equal to 15+ 15=30.