Question

Write the second smallest 7-digit number having four different digits.

Answer 1

The smallest 7-digit number = 1000000
According to the question, the number should have 4 different digits.
Two different digits (0 and 1) are already there in the smallest number, we need to use 2 and 3 which are next larger digits.
So, the smallest 7-digit number having four different digits = 1000023
Now, we are asked to find the second smallest 7-digit having four different digit.
So, the second smallest 7-digit number having four different digits = 1000032