Subtraction of Literals

Subtraction of Literals and their combination with the numbers follow the rules of subtraction of numbers.

If we are asked to subtract 5 from 7, then we write 7 – 5.

Exactly in the same way, when we are asked to subtract a number say 3 from a literal h, we write h – 3 and is read as ‘h minus 3’.

Note that h – 3 can also be read as ‘3 less than a literal number h’.

Similarly, if b is subtracted from a, we write a – b. We can also read a – b as ‘b less than a’.

If a subtracted from b, then we write b – a.

(a – b) – c means that b is subtracted from a and then c is to be subtracted from the result.

We can also say that c is subtracted from the difference of b from a.

It should be noted here that commutativity and associativity of subtraction are not true for literals as they are not true for numbers.

Examples of Subtraction of Literals:

Write each of the following phrases using number, literals and the basic operation of subtraction:

(i) 5 less than literal x

Answer: x – 5

(ii) 100 less than literal p

Answer: p – 100

(iii) Decrease x by 7

Answer: x – 7

(iv) Decrease m by n

Answer: m – n

(v) Subtract 4 from x

Answer: x – 4

(v) Subtract z from 50

Answer: 50 – z

(vi) x less than a sum of y and 7

Answer: (y + 7) – x

(vii) 10 less than a sum of x and y

Answer: (x + y) – 10

(viii) Decrease the sum of x and y by z

Answer: (x + y) – z

(ix) Decrease the sum of m and 10 by p

Answer: (m + 10) – p

(x) 5 is diminished by z

Answer: 5 - z

(xi) a less than 4

Answer: 4 - a

(xii) 4 less than x

Answer: x - 4

(xiii) Number m less than a number 10

Answer: 10 - m

(xiv) Number 7 less than a number s

Answer: s - 7

(xv) 25 taken away from y

Answer: y - 25

(xvi) x taken away from y

Answer: y - x