The density of a material in $CGS$ system of units is $4\,g\,cm^3$. In a system of units in which unit of length is $10\,cm$ and unit of mass is $100\,g$. the value of density of material will be
$M = d \cdot V $ $\Rightarrow d =\frac{ M }{ L ^{3}}$ $\Rightarrow d =\frac{4 \,gm }{ cm ^{3}}=\frac{4(1 / 100)}{10^{-3}} $ $=40 \frac{ gm }{ cm ^{3}}$
Atoms and molecules consist of very low mass. But they are present in huge numbers.
Chemists have to deal with numbers as large as 602,200,000,000,000,000,000,000, which is the number of molecules of 2g of hydrogen.
There are even other constants like the speed of light, charges on particles, Avogadro’s number and etc.
To handle these large or small numbers, we use the following notation: m × 10n, which is, m times ten raised to the power of n. In this expression, n is an exponent having positive and negative values and m is that number that varies from 1.000… and 9.999…
The scientific notation 573.672 can be written as 5.73672 × 102 and in the same way, 0.000089 can also be written as 8.9 × 10-5.
All of these help us to attain easier handling, better precision, and accuracy while performing operations on numbers with high magnitudes.