What is the pattern between - 4 to - 2.5

We will need more of the numbers to fully see a pattern. As of these two numbers it could be adding 1.5

L = - 4 + (n - 1) (0.5), where n represents which term (1, 2, 3, ...) and L represents the last term.

Step-by-step explanation:

We assume that this is an arithmetic sequence: L = A + (n - 1) D, where L is the last figure, A is the first and D is the common difference.

Here we have - 2.5 = - 4 + (n - 1) D, where neither n nor D is specified.

If we arbitrarily let D = 0.5, then the terms of the sequence are

{-4, - 3.5, - 3, - 2.5}, and n = 4:

Check: If n = 4, what is the last term? L = - 4 + (4 - 1) (0.5), or

L = - 4 + 3 (0.5) = - 4 + 1.5 = - 2.5

Assuming an arithmetic sequence, the pattern is

L = - 4 + (n - 1) (0.5)