Mass is the number of molecules/ matter/ or atoms present in an object.
The SI Unit of Mass is Kilogram represented by "kg".

Hii!
Mass is defined as the resistance to acceleration of a body when a net force is applied to it. It is the physical property of a body.
The SI unit of mass is kilograms ( Kg ).
You acn understand mass as a strength of its gravitational attraction to other bodies.
Hope this helps.
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