Question

What are the next 4 numbers in the pattern below 20, 15, 10, 5

Answer 1

0, -5, -10, -15 because it decreases by 5 every time

Answer 2

The pattern is that you subtract five to find the next number. 5-5 = 0. 0-5 = -5. -5-(-5) = 0. And so on and so forth.
The next 4 numbers are 0, -5, 0, and -5.
Hope that helped you.