What is the mass of a #405*mL# block of aluminium given that #rho_"Al"=2.70*g*mL^-1#?
The mass of the Aluminum would be 1100 grams
multiplying the Density by the volume will give the Mass
However 2.7 has only two measured significant number so the answer can not be more precise than the least precise measurement so the answer can only have two significant digits.
Rounding 1093.5 down to two digits gives
1100 grams as the best answer.