a) 900001

b) 900000

c) 811111

d) 900009

correct answer is: a) 900001

Explanation

We know,
Greatest number of 5 digits is ‘99999’ .
And, Least number of 7 digits is ‘1000000’ .
If we subtracted greatest number from the least number, we get:
\left(1000000-99999\right)
\rightarrow 900001
\therefore 900001 must be added to the greatest number.
Ans: 900001 must be added to the greatest number of 5 digits to have the least number of 7 digits.

Other versions of this specific question are:

1. Calculate the number needed to transform a 5 digit number into the smallest 7 digit number.
2. How to increase a 5 digit number to become the smallest 7 digit number?
3. Find the value to add to a 5 digit number to make it the smallest possible 7 digit number.
4. How to make a 5 digit number the smallest 7 digit number by adding what value?
5. What must be appended to a 5 digit number to make it the least 7-digit number?