Avogadro’s number can be defined as number of atoms present in one gram atom or the number of molecules present in 1 gram molecule of substance. Avogadro’s number is the conversion factor among number of moles and number of individual particles. (if we want to know the  number of atoms in an element we just multiply number of moles with Avogadro’s  number similarly if we want to know number of moles in an element we just divide number of atoms by Avogadro’s  number).

Mathematically,
Avogadro’s  number = Number of atoms /(number of molecules in one gram atom / mole).

As Avogadro’s number is defined in numbers it is a dimensionless quantity.

SI unit of Avogadro’s number is mole^-1.

Stress is defined as force applied on area.

Mathematically,
Stress = Force / Area

Dimensional Formula of Force= M¹L¹T^-2 [Check how Dimensional Formula of force is derived]
Dimensional Formula of Area= M⁰L²T⁰[Check how Dimensional Formula of area is derived]

Putting these values in above equation we get,
Dimensional Formula of Stress = (M¹L¹T^-2)/(M⁰L²T⁰)

Dimensional Formula of Stress = M¹L^-1T^-2
SI unit of Stress is Nm^-2

Dynamic viscosity can be defined as the tangential force per unit area required to slide one layer against other when two layers are maintained ad a unit distance.

Mathematically,
Dynamic viscosity = Stress ( Length / velocity).

Dimensional Formula of Stress= M¹L^-1T^-2
Dimensional Formula of Length =M⁰L¹T⁰
Dimensional Formula of velocity = M⁰L¹T^-1

Putting these values in above equation we get,

Dynamic viscosity = M¹L^-1T^-2 ( T¹)
Dynamic viscosity =M¹L^-1T^-1

Dimensional Formula of Dynamic viscosity = M¹L^-1T^-1
SI unit of Dynamic viscosity is Kg / ms

Kinematic viscosity is defined as the ratio of ability to diffuse a disturbance in momentum to ability of sustaining the original momentum.

Mathematically,
Kinematic viscosity (ν) = Dynamic viscosity (μ) / Density (ρ).

Dimensional Formula of Dynamic viscosity = M¹L^-1T^-1
Dimensional Formula of Density = M¹L^-3T⁰

Putting these values in above equation we get,
Dimensional Formula of Kinematic viscosity = M⁰L²T^-1
SI unit of Kinematic viscosity is m²s^-1

All physical quantities can be defined in terms of few fundamental physical quantities like Length, Mass and Time. The unit of these fundamental physical quantities or basic quantities are independent of  each other and no one can further resolve it into any other unit. There are 7 basic or fundamental physical quantities. They are Length, Mass, Time, Temperature, Electric Current, Luminous Intensity and Amount of  Substance.