Question

5th grade Help with Add and subtract fractions with unlike denominators

Answer 1

Addition of fractions with unlike denominators: 3/10 + 1/6 = 7/15

Subtraction of fractions with unlike denominators: 7/8 - 5/6 = 1/24

Step-by-step explanation:

"Unlike denominator" is said to have different numbers in the denominator.

• Change the unlike denominators to like denominators by finding the least common multiple (LCM) of the denominators.
• Now multiply the numerator and denominator with same number that gives the LCM in the denominator.
• Add or subtract the numerators according to the operator given, but do not perform any operation in the denominators.

Addition of fractions with unlike denominators:

⇒ Add 3/10 and 1/6.

⇒ Taking LCM  2 |10 6

                             |5   3  

⇒ The LCM is 2$\times$5$\times$3 = 30.

⇒ 3/10 + 1/6 = (3$\times$3)/(10$\times$3) + (1$\times$5)/(6$\times$5)

                     = 9/30 + 5/30

                     = 14/30 = 7/15

Subtraction of fractions with unlike denominators:

⇒ Subtract 7/8 and 5/6.

⇒ Taking LCM  2 |8 6

                             |4  3  

⇒ The LCM is 2$\times$4$\times$3 = 24.

⇒ 7/8 - 5/6 = (7$\times$3)/(8$\times$3) + (5$\times$4)/(6$\times$4)

                     = 21/24 - 20/24

                     = 1/24