Constants and Variables : Constants are fixed number and variables are literals.
The diameter, d of a circle of radius r is given by the formula d = 2r. In this formula, 2 is a fixed number whereas the literal numbers d and r are not fixed because they depend upon the size of the circle. For circles of different sizes, the values of d and r will be different.
It follows from the above examples that in Algebra, we come across two types of symbols namely constants and variables as defined below.
Constant : A symbol having a fixed numerical value is called a constant. OR
The number before an alphabet (variable) is called a constant.
Variable : A symbol which takes various numerical values is called a variable. OR
The alphabet after a number (constant) is called a variable.
In the formulas d = 2r; 2 is a constant whereas, r and d are variables.
Note: In some situations, literal numbers are also treated as constants. In such situations, it is presumed that the particular literal number will take a few fixed values.
Identify the constants and the variables in each of the following :-
i) 8a Solution :
Constant = 8 ; Variable = a
ii) 3d Solution :
Constant = 3 ; Variable = d
iii) 4t Solution :
Constant = 4 ; Variable = t
iv) ab Solution :
Constant = 0 ; Variable = ab
v) 44 Solution :
Constant = 44 ; Variable = none
vi) 21ac Solution :
Constant = 21 ; Variable = a and c
vii) 13r Solution :
Constant = 13 ; Variable = r
viii) 23s Solution :
Constant = 23 ; Variable = s
ix) 3 rd Solution :
Constant = 3 ; Variable = r and d
x) 24 th Solution :
Constant = 24 ; Variable = t and h