Question

Write the greatest and the smallest numbers of 4 digits that can be formed using the digits 0, 8, 7, 5 ; using each digit only once.

Answer 1

In order to write the largest 4-digit number using digits 0, 5, 7 and 8, we put the largest digit 8 at the place having the highest place value. The smallest digit 0 is put at the right most place i.e. at unit's place, the digit 7 is put at the hundred's place and the digit 5 is put at the ten's place. Hence, the required largest number is 8750.
In order to write the smalest 4-digit number using digits 0, 5, 7 and 8, we put the smallest digit 5 (Except 0) at the place having the highest place value. The largest digit 8 is put at the right most place i.e. at unit's place, the digit 7 is put at the ten's place and the digit 0 is put at the hundred's place. Hence, the required largest number is 5078.