The year 2015, which is about to end, has 7 consecutive days whose date numbers sum up to 100. What are the date numbers of these 7 days? $\qquad$
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【Analysis and Solution I Time and Date.
If these 7 days are in the same month, then the sum of the dates is the middle number $\times 7$;
and 100 is not a multiple of 7;
thus, these 7 days are in adjacent months.
$$
\begin{array}{l}
28+27+26=81,28+27+26+25=106>100 ; \\
30+29+28=87,30+29+28+27=114>100 ; \\
31+30+29=90,31+30+29+28=118>100 ; \\
1+2+3+4=10 ;
\end{array}
$$

Therefore, it can only be $100=29+30+31+1+2+3+4$;
that is, the dates of these 7 days are $29, 30, 31, 1, 2, 3, 4$.