Question

The difference between any number of four digits and the number formed by using the digits in the reversed order is exactly divisible by:

• A. $11$
• B. $10$
• C. $9$
• D. $5$

Answer 1

The correct option is C $9$

The difference between any number of four digits and the number formed by using the digits in the reversed order is exactly divisible by $9$.
For example, $1234$ is a 4-digit number if we reverse it then it would be$4321$.
Difference $=4321-1234=3087$
$3087÷9=343$
If we take another number $2345$ and reverse it$5432$ and subtract it then,

$5432-2345=3087$
$3087÷9=343$
Hence, the difference between any number of four digits and the number formed by using the digits in the reversed order is always divisible by $9$.