Question

Make the greatest and the smallest four digit numbers using any four different digits with condition as given.
Digit $9$ is always at hundreds place.

Answer 1

We know that there are ten digits in mathematics, that is, $0,1,2,3,4,5,6,7,8,9$

Step 1 : To make the greatest four digit numbers using any four different digits with given condition :

In order to write the greatest four digit number by using the digits $8,7,6$and $9$ is always at hundreds place, arrange the digits in descending order.

Thousands	Hundreds	Tens	Ones
$8$	$9$	$7$	$6$

The greatest four digit $=8976$

Step 2 : To make the smallest four digit numbers using any four different digits with given condition :

So, here smallest digits are $0,1,2$ .In order to write the smallest four digit number by using the digits $0,1,2$and $9$ is always at hundreds place, arrange the digits in ascending order. Also, keep $0$ at tens place.

Thousands	Hundreds	Tens	Ones
$1$	$9$	$0$	$2$

The smallest four digit $=1902$

Hence, the greatest and the smallest four digit numbers using any four different digits with condition $9$ is always at hundreds place are $8976$ and $1902$respectively.