The volume of a sphere is $1.76 \ cm^3$. The volume of $25$ such spheres in terms of significant figures is ...... $cm^3$.

Write the rules for rounding off numbers.

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

$Assertion$ : The number of significant figures depends on the least count of the measuring instrument.
$Reason$ : Significant figures define the accuracy of the measuring instrument.

Match the number of significant figures in the given column:

Column-$I$	Column-$II$
$(a)$ $0.007\ m^2$	$(p)$ $2$
$(b)$ $2.64 \times 10^{24}\ kg$	$(q)$ $1$
$(c)$ $0.0021\ g\ cm^{-3}$	$(r)$ $4$
$(d)$ $0.0006032\ J$	$(s)$ $3$

$A$ student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings: $5.50\, mm, 5.55\, mm, 5.45\, mm, 5.65\, mm$. The average of these four readings is $5.5375\, mm$ and the standard deviation of the data is $0.07395\, mm$. The average diameter of the pencil should therefore be recorded as: