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

(N/A) For multiplication and division involving significant figures,the following points must be considered:
$(1)$ In multiplication or division,the final result should retain the same number of significant figures as the original number with the least number of significant figures.
$(2)$ When a measurement is multiplied or divided by a definite number (an exact number like integers or fractions in physical equations),the result should have the same number of significant figures as the measurement.
For example:
$(1)$ If the length and breadth of a plate are $1.567 \text{ cm}$ and $10.4 \text{ cm}$ respectively,the area is $1.567 \times 10.4 = 16.2968 \text{ cm}^2$.
Since $10.4$ has $3$ significant figures (the minimum),the area should be rounded off to $16.3 \text{ cm}^2$.
$(2)$ If the mass of an object is $8.254 \text{ g}$ and its volume is $2.68 \text{ cm}^3$,then:
$\text{Density} = \frac{\text{mass}}{\text{volume}} = \frac{8.254}{2.68} = 3.07985074626 \text{ g cm}^{-3}$.
Since $2.68$ has $3$ significant figures,the result should be rounded to $3.08 \text{ g cm}^{-3}$.
$(3)$ If a number used in a calculation has an infinite number of significant figures,it should be rounded to a finite number of significant figures as required by the precision of the other measurements.
$(4)$ In equations,constants like $\pi, \epsilon_0, \mu_0$ should be rounded off to one digit more than the number of significant figures in the measurement with the least significant figures.