The area of a sheet of length $10.2 \,cm$ and width $6.8 \,cm$ expressed up to the proper number of significant figures is ......... $cm^2$.

The number of significant figures in $23.023$,$0.0003$,and $2.1 \times 10^{-3}$ are respectively:

"Trailing zeros in a number without a decimal point are not significant." Show that this statement is not always true.

What points should be considered during the multiplication and division of numbers with significant figures?

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