Suppose a is the largest number, A+ 1 is greater than a, and A+2 is greater than A+ 1. ......

The size of the comparison number must be within a certain range and meet certain conditions. For example:

Within an integer range, the largest single digit is 9, the largest two digits are 99, and so on.

Without certain conditions, it is impossible to compare. such as

What is the maximum number less than 10? Not sure yet.

For example, it is 9, 9.9 and 9.999999. These numbers are all less than 10, but they are not the largest. No matter what you name a number less than 10, you can always find a number greater than it but less than 10.