To get the largest two digits, the number of single digits and ten digits must be the largest, and 9 is the largest number of single digits, so the largest two digits are 99. In order to get the smallest two-digit number, the number on the unit and the tenth digit must be the smallest, 0 is the smallest single digit, and the tenth digit cannot be 0, so take 1 to get the smallest two-digit number, and the difference between them is 99- 10 = 89.

In the integer range, the largest two-digit number is 99, because 99 is a two-digit number and the largest one of the two digits. The smallest two-digit number is 10, because 10 is also a two-digit number, and it is the smallest number of two digits.

The difference between them is the largest two digits minus the smallest two digits. That is 99- 10=89. So the difference between the largest two digits and the smallest two digits is 89.

The importance of learning mathematics;

1. Mathematics is a key to our understanding of the world. From problems in daily life, such as shopping discounts and time management, to complex problems in science, technology, engineering and mathematics, mathematics is the basis for us to solve these problems and understand these fields.

Mathematics can cultivate our logical thinking and problem-solving ability. Mathematics involves a coherent logical way of thinking. Learning mathematics means that we need to understand problems, find solutions, reason and verify their effectiveness. This way of thinking is very useful in our daily life and work.

3. Mathematics is an important tool to promote human progress. Mathematics plays a key role in science, engineering, technology and economy. Without mathematics, we can't understand the laws of the universe, design complex machinery and communicate efficiently. In business, mathematics is also the basis for us to make predictions, formulate strategies and analyze data.

Mathematics can enhance our creativity and aesthetic feeling. From art to music, from architecture to design, mathematics is embodied in various forms of creation. Understanding mathematics can not only improve our creativity, but also enable us to better appreciate and understand the beauty around us.