Well, with 30 being the total amount, first subtract how much the bug had crawled up the first and second time!
30 - 14= 16
So now, what is left is 16, but since it climbs more, subtract again:
16 - 4 = 12ft
The answer is 12ft to go!
Another way you can do this is add the distances the bug crawled up!
14 + 4= 18
30 - 18= 12
Either way works!
Answer: 12ft
Hope this helped you out!