Question

Form the greatest and smallest $4-$digit numbers using any one of the given digits twice:

$3,7,0$

Answer 1

Step 1: Formation of the greatest $4-$digit number:

Use the largest value digit twice and arrange the digits in descending order for the largest number.

$7>3>0$
The required greatest number is $7730$
Step 2: Formation of the smallest $4-$digit number:

Use the smallest value digit twice and arrange the digits in ascending order for the smallest number

$0<3<7$
Since the smallest value digit is zero, place them in the second leftmost position.
The required smallest number is $3007$

Hence, the greatest and smallest $4-$digit numbers are $7730$ and $3007$ respectively.