For example, this topic: When Xiao Ming does addition, he regards a 0 with dozens of digits as 6 and another 8 with several digits as 3, and the result is 1054. What is the correct result?
Finding out the problem first is also the key, because the tenth 0 is regarded as 6, which means that the number has increased by 60, and because the 8 in the number is regarded as 3, which means that the number has decreased by 5, so the sum of this number has increased by 60-5=55.
These examples are just the tip of the iceberg. You have to draw inferences yourself. Finding out the key sentences of each application problem is a breakthrough.