Subtraction of Fraction

Fractions help us show parts of a whole. Sometimes we subtract one part from another. For example, if you eat part of a pizza and give another part away, how much is left? Let's learn how to subtract fractions easily!

Fractions can be subtracted if they have the same denominator.

1. Make denominators the same (find LCM if needed).
2. Subtract the numerators.
3. Keep the denominator the same.
4. Simplify if needed.

`5/6 – 2/6 = (5 - 2)/6`

            = `3/6 or 1/2`.

Subtract `1/5` from  `1/2`.

1. Find a common denominator:
   Least Common Multiple (LCM) of 2 and 5, which is 10.
   
   
2. Convert both fractions to have the denominator of 10:
   ⇒ `1/2 = (1 xx 5)/(2 xx 5) = 5/10`
   
   ⇒ `1/5 = (1 xx 2)/(5 xx 2) = 2/10`
   
   
3. Subtract the fractions:
   `5/10` – `2/10` = `"(5 – 2)"/10` = `3/10`

Note that 10 is the least common multiple (LCM) of 2 and 5.

Subtract 3`2/5` –  2`1/7`
Method I:
 3`2/5` –  2`1/7` = (3 - 2) + (`2/5`-`1/7`)

                   = 1 + `"2 × 7"/"5 × 7"` - `"1 × 5"/"7 × 5"`

                   = 1 + `14/35` - `5/35`

                   = 1 + `9/35`

                   = 1`9/35`
Method II :
3`2/5` –  2`1/7` = `17/5` – `15/7`

                    = `"17 × 7"/"5 × 7"` –  `"15 × 5"/"7 × 5"`

                   = `119/35` - `75/35`

                    = `"119 - 75"/35`

                    = `44/35`

                    =1`9/35`

Ayaan has `3/4` of a chocolate bar. He gives `1/2` to a friend. How much chocolate does he have left?

• LCM = 4

• 3 − 2 = 1

• Answer: `1/4` of the chocolate bar left.

• Always get common denominators before subtracting if denominators are different.

• Subtract only the numerators; keep the denominator the same.

• Simplify your fraction at the end.