Question

Is the sequence –9.9, –13, –16, –19.2, … arithmetic? If so, identify the common difference.

Answer 1

???

Answer 2

Can you give it a try first?

Answer 3

-9.9 + ? = -13
-13 + ? = -16
-16 + ? = -19.2

Does the same number replace the "?" in all three? If it does then it's arithmetic and that number is the common difference. If not, it's not arithmetic.