1, the maximum number to fill in: to find the maximum number of three digits, it is necessary to consider that this number will not exceed 999, because the range of three digits is 100-999. So, the biggest number is 9.

2. Maximum number of integers: If we ask how much the largest integer in a three-digit number can be filled, we need to consider that the range of this integer is -99 to 99, because the integer does not include 0 before the decimal point and 0 after the decimal point. So, the largest integer is 99.

3. Odd or even number of the largest number to be filled: If we ask how much the largest odd or even number in a three-digit number can be filled, we need to consider the range of this number from -99 to 99, because the range of odd and even numbers is infinite. So the largest odd and even numbers are both 99.

4. Maximum number divisible by 3: If we ask how much the maximum number divisible by 3 in a three-digit number can be filled, we need to consider that the sum of all digits of this number must also be a multiple of 3. Therefore, the maximum number that can be filled in is 996.

5. Maximum number divisible by 7: If we ask how much the maximum number divisible by 7 can be filled in a three-digit number, we need to consider that the last number of this number must be one of 0, 3, 6 and 9. Therefore, the maximum number that can be filled in is 984.

Methods of training logical thinking:

1, reading mystery novels: this is an effective way to improve logical thinking ability. Mystery novels need readers to reason according to clues, so as to get answers. This kind of training helps to improve our reasoning and observation ability.

2. Learning programming: Programming involves logic and mathematics. By writing code, we can understand and use various logical structures, such as conditional statements and loops.

3. Do math problems: Mathematics is a basic logic subject. By doing math problems, we can exercise our logical thinking ability and improve our problem-solving ability.

4. Play logic games: for example, board games, Sudoku, etc. These games require us to use logical thinking to win.

5. Learning philosophy: Philosophy requires us to think logically so as to understand the world. By studying philosophy, we can improve our logical thinking ability.