we are adding 2 each time
1,3,5,7,9,11,13,15,17,19,21,23,25,27,29
The 9th term is 17
As you can see they are just adding 2 to each of the numbers.
1
1 + 2 = 3
3 + 2 = 5
5 + 2 = 7
7 + 2 = 9
9 + 2 = 11
11 + 2 = 13
13 + 2 = 15
15 + 2 = 17
The ninth term is 17.
Hope this helps! Happy thanksgiving, here's a turkey!