Scalars are numbers that are used to measure size, or how big or small something is. They represent the magnitude of a quantity such 12.5 miles, or 34 degrees C.
Numbers that are used to count things are not considered scalars, although you can do arithmetic with them.
For example 2 apples + 3 apples = 5 apples.
For more see Counting numbers.
Identifying numbers are not scalars and are used to identify something or act as an identifying label. For example a phone number, or student id number are not scalars. You cannot do arithmetic with them. For example, dividing a phone number by three has no meaning.