4. (8 points) In the equation on the right, different Chinese characters represent different digits, and the same Chinese characters represent the same digits, making the equation true. Therefore, the four-digit number “望子成龙” is $\qquad$ .


【Solution】Solution: According to the problem, we have:
Dragon + Dragon + Dragon's unit digit is 2, so we have $3+3+3+3$ or $8+8+8+8$.
When Dragon $=3$, Cheng + Cheng + Cheng plus a carry-over unit digit is 1, without a carry-over unit digit is 0, there is no number that meets the condition. When Dragon $=8$, Cheng + Cheng + Cheng plus 3 carry-overs unit digit is 1, then Cheng + Cheng + Cheng unit digit is 8, then $6+6+6$ satisfies the condition.

Zi + Zi plus 2 carry-overs unit digit is 0, at the same time, Zi + Zi plus 2 carry-overs cannot carry over 2 to the thousand's place, then Zi $=$ 4 satisfies the condition.

Wang plus 1 carry-over equals 2, Wang $=1$.
Therefore, the answer is: 1468