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Subtraction of algebraic expressions:

 The simplest expressions are monomials.

 They consist of only one term.

 So while subtracting monomials we just need to add the digits and keep the

variable as it is.
 Ex- Let us add 4x and 3x

4x + 3x = (4 × x) - (3 × x)
= (4 - 3) × x (using distributive law)

= 1 × x = 1x or x

or 4x - 3x = 1x or x.
 Except monomials in the rest case while subtracting we have separate the like

terms and unlike terms, then add the like terms by keeping the variable same

and the unlike terms with remain as it is.
 Note- Unlike terms cannot be added or subtracted the way like terms are

added or subtracted.

 The difference between two like terms is a like term with a numerical
coefficient equal to the difference between the numerical coefficients of the

two like terms.
 The subtraction can be done horizontally and vertically also.

 Ex- Subtract 24ab – 10b – 18a from 30ab + 12b + 14a.

Solution: 30ab + 12b + 14a – (24ab – 10b – 18a)
= 30ab + 12b + 14a – 24ab + 10b + 18a

= 30ab – 24ab + 12b + 10b + 14a + 18a
= 6ab + 22b + 32a

 Alternatively, we write the expressions one below the other with the like terms

appearing exactly below like terms as:
30ab + 12b + 14a

24ab – 10b – 18a
– + +

6ab + 22b + 32a