最小的三位数是多少？

表示数字或使用数字的方法称为数字系统。数字系统是数字或表达数字的数学表示。它也可以定义为用于通过使用符号/数字来表示给定集合的数字的数学符号。它允许进行算术运算，例如除法、乘法、加法、减法。

最常用的数制是十进制数制，十进制是指用0、1、2、3、4、5、6、7、8、9这10个数字来构造所有需要的数字。一些重要的数字系统如下，

1. 十进制数系统
2. 二进制数制
3. 八进制数系统
4. 十六进制数系统

三位数的最小数是多少？

回答：

The Smallest three-digit number in the number system is 100. The smallest 3 digit number in the number system is 100 because if 1 is subtracted from the number it becomes a 2 digit number which is 99 (a two-digit number). So 100 is the smallest 3 digit number in the number system.

Smallest three digit number in the number system = 100

=  100 – 1  

=  99 (which is a 2 digit number)

Hence it is proved that 100 is the smallest three-digit number.

如果所有数字都是唯一的，那么最小的 3 位数字是多少？

回答：

As in the above explanation that 100 is the smallest 3 digit number in the number system. Find the smallest 3 digit number will all be unique digits. First, write the numbers which have 3-digits starting from 100 and then look for the smallest 3-digit number with all unique digits. 

Thus we get,  

100, 101, 102, 103, 104, 105, 106, 107…

Next, find the number which has all the unique digits in it.

Explanation – In number 100, the digit 0 is repeating two times.  So, 100 is not considered. Next, check for the number 101, in which 1 is repeating twice hence it is not considered. Next, consider the number 102, as no digits are repeated and it has all the 3 unique digits.

• 100 – (Digit 0 is repeating twice)
• 101 – (Digit 1 is repeating twice)
• 102 – (All digits  are unique)

Thus, 102 is the smallest 3-digit number with all its unique digits.

类似问题

问题1：最小的1位数字是多少？

回答：

The smallest 1 digit number in the number system is 0.

问题2：最大的1位数是多少？

回答：

Largest 1 digit number in the number system 9.

问题3：最小的两位数是多少？

回答：

Smallest 2 digit number in the number system is 10.

问题4：最大的两位数是多少？

回答：

Largest 2 digit number in the number system 99.

问题5：最小的4位数字是多少？

回答：

The smallest 4 digit number in the number system is 1000, if 1 is subtracted from the number it becomes 3 digit number that is 999 (Three digit number). So 1000 is the smallest 4 digit number in the number system.

Smallest 4 digit number = 1000

= 1000 – 1

= 999 (Which is 3 digit number)

So it is proved 1000 is the smallest 4 digit number in the number system.

问题6：最大的4位数字是多少？

回答：

The largest 4 digit number in the number system is 9999. If +1 is added to the number (9999) it becomes 5 digit number that is 10000 (a five-digit number). So 9999 is the largest 4 digit number in the number system.

Largest 4 digit number = 9999

= 9999 + 1

= 10000 (Which is 5 digit number)

So it is proved the 9999 is the largest 4 digit number in the number system.

问题 7：最小的 5 位数字是多少？

回答：

The smallest 5 digit number in the number system is 10000, if we subtract -1 from the number it becomes 4 digit number that is 9999 (Four-digit number). So 10000 is the smallest 5 digit number in the number system.

Smallest 5 digit number = 10000

= 10000 – 1

= 9999 (Which is 4 digit number)

So it is proved the 10000 is the smallest 5 digit number in the number system.

问题8：最大的5位数字是多少？

回答：

The largest 5 digit number in the number system is 99999, If 1 is added +1 to the number ( 99999 ) it becomes 5 digit number that is 100000 (Six-digit number). So 99999 is the largest 5 digit number in the number system.

Largest 5 digit number = 99999

= 99999 + 1

= 100000 (Which is 6 digit number)

So it is proved the 99999 is the largest 5 digit number in the number system.