Question

Why are multiples and submultiples of $SI$ units required$?$

Answer 1

We may use a variety of objects as length measurement units. Prefixes are used to get a bigger value or a smaller value for regular units. The product of any calculation consists of numbers and names. The basic unit includes multiples and submultiples.

Useful formula:
Multiples and Submultiples of the meter.

Factor	MultiplesName	submultiplesName
${10^1}$	$dac$	$dm$
${10^2}$	$hm$	$cm$
${10^3}$	$km$	$mm$

Where,
${\text{km}}\left( {{\text{kilometre}}} \right)$, ${\text{hm }}\left( {{\text{hectometre}}} \right)$, and ${\text{dac}}\left( {{\text{decametre}}} \right)$.
${\text{Dm (decimetre), cm}}\left( {{\text{centimetre}}} \right){\text{ }}$, and ${\text{mm }}\left( {{\text{millimetre}}} \right)$.

Complete step by step process:
Multiples of $SI$ units:
When a larger distance is to be covered, we cannot use meters. So to cover a larger distance we use ${\text{km}}\left( {{\text{kilometre}}} \right)$, ${\text{hm }}\left( {{\text{hectometre}}} \right)$, and ${\text{dac}}\left( {{\text{decametre}}} \right)$. These are called the multiples of Meter.
The size of the SI unit is either too small or too big to measure a certain quantity.
For example,
A meter is too small a unit to measure the distance between two cities and too big a unit to measure the thickness of a wire.
Measurement is a process of comprising an object with a standard unit of measurement. a standard unit of measuring length is called a meter.
Submultiples of $SI$ units:
When the distance is smaller, we use ${\text{Dm (decimetre), cm}}\left( {{\text{centimetre}}} \right){\text{ }}$, and ${\text{mm }}\left( {{\text{millimetre}}} \right)$These are called the submultiples of Meter.
Multiples are factors used to create larger forms whereas submultiples are factors used to create smaller forms of the SI units.
For example,
A centimeter is a submultiple and kilometer is a multiple of a meter.

Hence multiples and submultiples of $SI$ units are required

Note: The multiples and submultiples of the meter were formed by adding some Greek and Latin prefixes to communicate distances larger and smaller than the meter more accurately. The unit value is from ten to ten, the same as our numbering system. This helps unit conversion.