M = V ρ = l \cdot S \cdot ρ = 1 m \cdot 0, 0001 m^{2} \cdot 2700 k g / m^{3} = 0, 27 k g

${M ={V}{\rho} = l\cdot S\cdot \rho={1}\,\mathrm{m}\cdot {0,0001}\,\mathrm{m^2} \cdot {2700}\,\mathrm{kg/m^3} = {0,27}\,\mathrm{kg}}$

Error