The difference between a number of two digits and the number obtained by interchanging its digits is 18. How much is the difference between both digits of that number ?

Explanation

To solve the problem step by step, we will define the two-digit number and set up an equation based on the information given.

### Step 1: Define the digits
Let the two-digit number be represented as \( AB \), where \( A \) is the tens digit and \( B \) is the units digit.

### Step 2: Express the number mathematically
The numerical value of the number \( AB \) can be expressed as:
\[
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