Identify a pattern and find the next number in the pattern.

Well you didnt list a pattern so if you need to learn a pattern how about maybe ...

3 6 9 12 15

Adds 3 every time

9, 4.5, 2.25, 1.125

Divides 2 everytime

Just do the opposite of whatever mathematic system youre using to find the pattern.

Like maybe add 4.5+4.5 and it would be 9. Like

It would turn into a whole new equation

Find for 9.

or find for 6.