Differences between the Greatest Two-Digit Number and the Smallest Three-Digit Number
The greatest two-digit number is 99, while the smallest three-digit number is 100. Let's explore the differences between these two numbers in detail.

Greatest Two-Digit Number (99)
- The greatest two-digit number is composed of two digits, 9 and 9.
- It is the largest number that can be formed using only two digits.
- It is one less than 100, the smallest three-digit number.
- When compared to other two-digit numbers, 99 is the highest possible value.

Smallest Three-Digit Number (100)
- The smallest three-digit number is composed of three digits, 1, 0, and 0.
- It is the beginning of the three-digit number series.
- It is one more than 99, the greatest two-digit number.
- It is the smallest number that requires three digits to represent.

Key Differences
- The greatest two-digit number has two digits (9 and 9), while the smallest three-digit number has three digits (1, 0, and 0).
- The greatest two-digit number is 99, while the smallest three-digit number is 100.
- The difference between the greatest two-digit number and the smallest three-digit number is 1.
- The greatest two-digit number is the highest possible value in two digits, while the smallest three-digit number is the beginning of the three-digit number series.
In conclusion, the greatest two-digit number and the smallest three-digit number differ in their composition, value, and the number of digits required to represent them. The greatest two-digit number represents the highest value possible with two digits, while the smallest three-digit number marks the beginning of the three-digit number series.

100-99=1