Solve the cryptarithm : ` A B + B A =\ D A D \ `

Explanation

To solve the cryptarithm \( AB + BA = DAD \), we need to interpret the letters as digits. Let's break down the problem step by step.

### Step 1: Understand the representation of the numbers
- Let \( AB \) represent the two-digit number where \( A \) is the tens digit and \( B \) is the units digit. Thus, \( AB = 10A + B \).
- Similarly, \( BA \) represents the two-digit number where \( B \) is the tens digit and \( A \) is the units digit. Thus, \( BA = 10B + A \).
- The expression \( DAD \) represents a three-digit number where \( D \) is the hundreds digit, \( A \) is the tens digit, and \( D \) is the units digit. Thus, \( DAD = 100D + 10A + D = 101D + 10A \).

### Step 2: Set up the equation
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