How do numbers play a role in biological design?

When I look out into a forest I see lots of things. What I don’t see is some sort of true relationship with numbers. Are numbers arbitrary? Does the physics of the universe really care about one, as opposed to two?

Where are the numbers hiding? Is our interaction with the world a math problem that we keep solving without consciously thinking about it?

Say I pick up a turkey sandwich (my favorite) and take a bite. I know lots of math and numbers exist in that situation, I just can’t understand how it can be so “quiet”?

I see that I have five fingers! I see that a leaf can have three points. But was this design really focusing on a number or rather practicality.

My vote is practicality. So is practicality where the numbers are at the forefront? Is it the internal counting of the decision ballot box that has the most to do with the situations I am thinking of?

I can’t imagine this is very clear, please feel free to help me get a grip on what I am asking!