It is essential to convert the units whenever there is a need to solve the problems. It is essential to do the mathematical conversions to carry the basic calculations.
For, e.g. to find the area of a triangle. You need to check if the base is given in cm, and height is given in meters, and you are asked to find the area of a triangle in cm; it is important to convert the height in meters into centimetres. Therefore, it is crucial to know the concept of conversion of units into the required unit.
The usage of the unit depends on the situation. E.g., you can see that the area of a room is expressed in meter form. While, when we see, the length of the pencil is expressed in centimetres and its thickness in mm.
Therefore, it is essential to convert one unit to the other. Thus, before you understand the concept of conversion, it is best to know the relation between the units first.
It is clear that Menstruation is the old concept and to know the physical quantity like Mass, Length, Time, temperature, etc. All these have a specific unit. And, in terms of definition, a unit is termed as a magnitude of a physical quantity.
In general, there are two systems of units:
For example, the SI unit of length is a metre (m), while metric units are kilometre (km), meter (m), decimetre (dm), centimetre (cm) and millimetre (mm).
SI unit of mass is Kilograms (kg).