Difference of the smallest 6 digit number and the greatest 4 digit number is
A. 1
B. 90000
C. 90001
D. 900001

Hint: The smallest 6 digit number is 100000 and the greatest 4 digit number is 9999. Subtracting both the numbers would give the answer.

Complete step-by-step answer:
Before proceeding with the question, we must know what is the smallest 6 digit number and what is the greatest 4 digit number. We must also know how to form the smallest 6 digit number and the greatest 4 digit number. The smallest 6 digit number is 100000 because when we subtract 1 from 100000, we get a 5 digit number. Therefore, 100000 is the smallest 6 digit number. The greatest 4 digit number is 9999 because when we add 1 to it, we get a 5 digit number. Therefore, 9999 is the greatest 4 digit number.
Therefore, we have to find out the smallest 6 digit number and the greatest 4 digit number and then compute their difference.
We know that the smallest 6 digit number is 100000 and the greatest 4 digit number is 9999.
According to the question, we have to find the difference between the smallest 6 digit number and the greatest 4 digit number. So, we can write it as,
100000 - 9999 = 90001
Therefore, we get 90001 as the difference of the smallest 6 digit number and the greatest 4 digit number.
Hence, we have obtained the correct answer as option C.

Note: We can use the trick to form the largest and the smallest number. The largest number of any digit is formed by placing all the digits with 9. The smallest number of any digit is formed by placing 1 and replacing the other digits by 0. Like for example, the largest 8 digit number is 99999999 and the smallest 5 digit number is 10000.