Question

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

$5,7,0$

Answer 1

Step 1: Use the largest value digit twice and arrange the digits in descending order for the largest number.

$7>5>0$
The required greatest number is $7750$
Step 2: Use the smallest value digit twice and arrange the digits in ascending order for the smallest number

$0<5<7$
Since the smallest value digit is zero, place them in the second leftmost position.
Hence, The required smallest number is $5007$