To find the next number in the arithmetic sequence, we first need to determine the common difference. An arithmetic sequence has a constant difference between consecutive terms.

Let's calculate the common difference:

• From $-20$ to $-32$: $-20 - (-32) = 12$
• From $-8$ to $-20$: $-8 - (-20) = 12$
• From $4$ to $-8$: $4 - (-8) = 12$

Thus, the common difference is $12$.

Now, to find the next number in the sequence, add $12$ to the last term, $4$:

$4 + 12 = 16$

Therefore, the next number in the sequence is 16.

Would you like more details or have any questions?

Here are some related questions:

1. What is the general formula for the nth term of this arithmetic sequence?
2. How do you find the sum of the first n terms in an arithmetic sequence?
3. Can an arithmetic sequence have a negative common difference?
4. What are the properties of arithmetic sequences compared to geometric ones?
5. How do arithmetic sequences relate to linear functions?

Tip: In any arithmetic sequence, once you identify the common difference, you can easily calculate any term using the formula for the nth term.