We're given:
\[
\text{ABC} \times \text{DEED} = \text{ABCABC}
\]
Let:
- ABC be a 3-digit number, i.e. \( 100A + 10B + C \)
- DEED be a 4-digit number, i.e. \( 1000D + 100E + 10E + D = 1001D + 110E \)
So the expression becomes:
\[
(100A + 10B + C) \times (1001D + 110E) = 100000A + 10000B + 1000C + 100A + 10B + C
\Rightarrow \text{ABCABC}
\]
We test values via trial and error.
Try:
- ABC = 123
- DEED = 1001 × 1 + 110 × 0 = 1001
Then:
\[
123 \times 1001 = 123123 = \text{ABCABC}
\Rightarrow \boxed{D = 1, E = 0}
\]