The mass of a box is $2.3\, kg$. Adding $2.15\, g$ and $12.39\, g$ to it,the total mass is ........ $kg$.

An object of mass $4.237 \, g$ occupies a volume of $1.72 \, cm^3$. The density of the object to appropriate significant figures is ......... $g \, cm^{-3}$.

The volume of a sphere is $1.76 \ cm^3$. The volume of $25$ such spheres,taking into account significant figures,is:

State the number of significant figures in the following:
$(a)$ $0.007 \;m^{2}$
$(b)$ $2.64 \times 10^{24} \;kg$
$(c)$ $0.2370 \;g \;cm^{-3}$
$(d)$ $6.320 \;J$
$(e)$ $6.032 \;N \;m^{-2}$
$(f)$ $0.0006032 \;m^{2}$

The length of the side of a cube is $1.2 \times 10^{-2} \ m$. Its volume up to correct significant figures is

The radius of a disc is $1.2 \; cm$. Its area according to the concept of significant figures will be given by