【7】There is a sequence of numbers, arranged in the order of $345267345267 \cdots$. The sum of the first 50 numbers is $(\quad)$.
【Key Point】Periodic problem.
【Analysis】345267 is a cycle. $50 \div 6=8$ (groups) ..... 2 (items),
$$
(3+4+5+2+6+7) \times 8+3+4=27 \times 8+7=216+7=223
$$

【Answer】223