The largest three digits are 999, and the smallest four digits are1000; 1000-999= 1; So the difference between the largest three digits and the smallest four digits is 1.

The largest three digits are 999. The digits of natural numbers are called digits; A number containing a number is a number; Numbers containing two digits are two digits; Three digits is three digits ... the number of n digits is n digits. The largest three digits need a hundred digits, and all the digits in the ten digits are the largest, so the largest three digits can get 999.

The smallest four digits are1000; The largest four digits are 9999. The maximum number of digits is 9 and the minimum number of digits is1; The maximum two digits are 99, and the minimum two digits are 10. Number of digits refers to the number of digits of natural numbers. One digit: 1, 3, 5, 7, etc. Two digits: 10, 24, 66, 89, etc. Multi-digit means that a number containing two or more digits is multi-digit, such as 888, 9874, etc.

Number of digits in mathematics: the largest digit is 9, the smallest digit is 1, the largest two digits are 99, and the smallest two digits are 10. For the integer n, its digits are [log( 10)(n)+ 1]. Music digits: The attributes of music files include artist, release year, duration, type (.mp3 or. Wma and so on. ), number of digits, size, etc.

Application of mathematics

1, to meet the needs of people's daily life, work, counting, calculation and reasoning. In people's daily life and work, it is essential to count things, calculate various quantities and compare related quantities. Mathematical knowledge and thinking methods are needed here.

2. Exercise people's thinking level and thinking quality, such as calculation ability, logical thinking ability and spatial imagination ability.

3. Mathematics learning can provide necessary technical support for further study of natural science and social science. Mathematics, as a basic subject to understand the world, can support the in-depth development of different applied sciences ideologically and technically like a computer system, which should be deeply understood and experienced by people with higher education.

4. Learning mathematics can help us understand and learn the scientific and rigorous scientific attitude and style embodied in mathematicians, and improve our scientific literacy.