Why doesn't this equal 16?

This is from a larger equation, which I kept trying to solve it like this:

-4^{2-(-3+5)÷(-1)*2}

16-2÷(-1)2 16-(-2)2 16-(-4) 16+4 20

I kept solving this by assuming -4² is 16, and I can't figure out why it's not.

This is from a larger equation, which I kept trying to solve it like this:

-4^{2-(-3+5)÷(-1)*2}

16-2÷(-1)2 16-(-2)2 16-(-4) 16+4 20

I kept solving this by assuming -4² is 16, and I can't figure out why it's not.