The smallest 4-digit number having distinct digits is

1. 1234

2. 1023

3. 1002

4. 3210

The largest 4-digit number having distinct digits is

1. 9999

2. 9867

3. 9786

4. 9876

The difference between the largest number of 3-digit and the largest number of 3-digit with distinct digits is

1. 0

2. 10

3. 12

4. 14

If we write numbers from 1 to 100, the number of times the digit 5 has been written is

1. 11

2. 15

3. 19

4. 20