2020年希望杯二年级竞赛模拟第30题 其它
There are $13$ kids in line. They are numbered following the pattern: $1$, $2$, $3$, $4$, $5$, $1$, $2$, $3$, $4$, $5$, and so on. How many kids are numbered with odd numbers? 
Overseas Competition->Knowledge Point->Counting Modules
$13\div5=2R3$  There are $3$ odd numbers in each cycle.  $3\times2+2=8$ 