2. Find the least common denominator
(LCD) of the following sets of
fractions.
1. 1/3 , 1/5
2. 1/7 , 5/8
3. 2/3 , 1/6
4. ¾ , 1/2
5. 3/5 , 1/10
3. Study and Learn
Sarah bought ½ kilogram of
lanzones and ¼ kilogram of grapes
for her grandmother. How many
kilograms of fruits did she buy in
all?
What shall we do to solve the problem?
We shall add.
4. What are we going to add?
½ and ¼
What kind of fractions are ½ and ¼?
They are dissimilar fractions.
Do you know how to add dissimilar fractions?
Look closely as we solve the problem.
5. Through Illustration
Change to similar
fractions ½ + ¼
2/4 + ¼
Add the
numerators
and use the
same
denominators
2/4 + ¼ =3/4
6. By computation
Step 1
Find the least common denominator
1
2 4
1
4 4
=
=
Step 2
Find fractions equal to the given fraction
1 2 2
2 2 4
1 1
4 4
x =
=
Step 1
Add the numerators and use the common
denominators. Reduce to lowest if possible.
3
4
=
7. Let’s have another example
3 3 5 15 15
9 45 9 5 45 45
+ 3 3 9 27 27
5 45 5 9 45 45
43
45
The sum is 43
45
= x =
= x =
=
8. Solve and copy the correct answer on your paper.
1)
2)
3) 2/3 + ¼ = ( 8/12, 10/12, 11/12)
2/5 + ½ + ¼ = (1 3/20, 1 1/20, 1 5/20)
3/4 + 5/6 + ½ = (2 3/12, 2 2/12, 2 1/12)
9. In adding dissimilar fractions, follow these
steps:
● Find the LCD of the given fractions.
● Change the fractions into similar
fractions.
● Add.
Always express the answer in lowest
terms.
