a) $\dfrac{1}{2}x^2.(-2x^2y^2z).\dfrac{-1}{3}x^2y^3$
$=[\dfrac{1}{2}.(-2).\dfrac{-1}{3}].(x^2.x^2.x^2).(y^2.y^3).z$
$=\dfrac{1}{3}x^6y^5z$
Bậc: $6+5+1=12$
b) $(-x^2y)^3.\dfrac{1}{2}x^2y^3.(-2xy^2z)^2$
$=(-1)^3.(x^2)^3.y^3.\dfrac{1}{2}x^2y^3.(-2)^2.x^2.(y^2)^2.z^2$
$=-x^6y^3.\dfrac{1}{2}x^2y^3.4x^2y^4z^2$
$=-2x^{10}y^{10}z^2$
Bậc: $10+10+2=22$