
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Let $A$, $B$, $C$, and $D$ be digits. Consider the following arithmetic operations where $A$ and $C$ form two-digit numbers with a shared tens digit $E$ (a digit) as $EA$ and $EC$. Solve the problems:
1. $\begin{tabular}{ccc}&E&A\\ +&E&C\\ \hline &D&A\end{tabular}$
2. $\begin{tabular}{ccc}&E&A\\ -&E&C\\ \hline &&A\end{tabular}$
Determine the digit that $D$ represents.
A) 2
B) 4
C) 6
D) 8
E) 9

Present the answer in LaTex format: \boxed{Your answer}
user