1, we can think of it this way: if a+b is regarded as a-b, the result will be reduced by two B's, which is just 9.3, and 1 B is 4.65, then A is 4.65+7.5= 12. 15 (that is, a very large one.

2、( 1)25.002(2)250.02

3. Originally it was a+2.4, but it was mistaken for a+24=38.6, so A = 38.6-24 = 14.6, 14.6+2.4 = 17.

Problem (1) and problem (3) can be regarded as very simple reduction problems, and the relationship between addition and subtraction parts should be combined. (2) It should be analyzed according to the reading rules of integers and decimals.

When solving problems, there is no need to classify them into a certain category. The key is to analyze the meaning of the problem and find the appropriate knowledge to solve it comprehensively.