Answer:
t×4
Explanation:
5×4=20
20×4=80
80×4=320
To get from 5 to 20 you might try to add but you will see that it won't work to get the rest of the pattern. So to get to 20 from 5 you multiply by 4. If you continue to follow the pattern you will see that this way works so the answer is t×4.