Question

Write the greatest and the smallest four digit numbers using any $4$-digits obeying the following conditions:

Condition	Smallest $4$-digit number	Greatest $4$-digit number
The digit $5$ is always at tens place
The digit $9$ is always at ones place
The digit $7$is always at thousands place

Answer 1

Condition	Smallest $4$-digit number	Greatest $4$-digit number
The digit $5$ is always at tens place	$1050$	$9959$
The digit $9$is always at ones place	$1009$	$9999$
The digit $7$is always at thousands place	$7000$	$7999$

(i) When digit $5$ is always at tens place ,The Smallest $4$-digit number is $1050$ and largest $4$- digit number is $9959$

(ii) When digit $9$ is always at tens place ,The Smallest $4$-digit number is $1009$ and largest $4$- digit number is $9999$

(iii) When digit $7$ is always at tens place ,The Smallest $4$-digit number is $7000$ and largest $4$- digit number is $7999$.