Write the smallest 4 digit number formed using the digits 8,3,0,1.
A) 1038
B) 1308
C) 1803
D) 0138

Hint:
According to the given question, we have to find the smallest 4 digit number with the help of 4 different numbers. Here, we can apply the logic of lowest and highest numbers or we can use ascending or descending order to find the answer.

Complete step by step solution:
As we are given with the four different digits that are 8, 3, 0, 1 and we have to calculate the smallest 4 digit number.
Firstly, we will arrange the given numbers in an ascending order.
Hence, we get \[0 < 1 < 3 < 8\]
Therefore, the smallest 4 digit number that can be formed using the digits 0, 1, 3 and 8 without repeating any digit.
As, we can observe that 138 is a three digit number formed and in the question it has been asked to find the 4 digit number. So, 138 cannot be formed as a smallest digit. So, we have to change the place of 0 and 1 to get the 4 digit number.
Thus, we get 1038, which is now a smallest 4 digit number.
Hence, 1038 is the smallest 4 digit number that can be formed using the digits 8, 3, 0, 1.

So, option (A) 1038 is correct.

Note:
To solve these types’ questions in which 0 digit is given, then we must remember that in the question it has been asked for a 4 digit number. But, students make mistakes by writing 0138 as an answer which is totally wrong. Hence, it becomes a three digit number which is not asked.