Adding/Subtracting Polynomials

What kind of polynomial is this?

$$x^2+3x^5+9$$  

How many terms are there?

$$3x^3+2x^2+4x+4$$  

What is the degree of the polynomial?

$$2x^5+4x+3$$  

Add the polynomials $$\left(x^2-2\right)$$  and $$\left(x^2+3\right)$$  

Add these polynomials:

$$\left(5x+2\right)+\left(4x+5\right)$$  

Add these polynomials:

$$\left(2x+5y-z\right)+\left(-6x-4y+7z\right)$$  

Subtract the following:

$$\left(4x^2+x\right)-\left(x^2+2x\right)$$  

Subtract:

$$\left(4n^4-8n+4\right)-\left(8n^2+4n^4+1\right)$$  

Subtract:

$$\left(x^5+3x\right)-\left(6x-x^3+6x^5\right)$$  

How much do you agree with the statement:

I can add and subtract polynomials!