Common ratio means it's referring to multiplication and division
Common difference means it's referring to addition or subtraction
If you want to find the common ratio, take two numbers that are next to each other, like -16 and 8
And divide the next number by the previous number: -16/8
So the common ratio would be -2.
8/-4 = -2
-16/8= -2
32/-16= -2
They all have -2 in common!