Math

1. SLIDESMANIA
SLIDESMANIA
Good Morning Grade 5!

2. SLIDESMANIA
SLIDESMANIA

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Number and
Number Sense
1.1 Addition of Fractions
1.2 Subtraction of Fractions
1.3 Problem Solving Involving
Addition and Subtraction of
Fractions

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At the end of the discussion, you will be able to:
• Find the least common denominator (LCD).
• Add and subtract fractions and mixed numbers with
or without regrouping.
• Solve word problems involving addition and
subtraction of fractions using appropriate strategies
and tools.

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SLIDESMANIA
Read the following fractions.

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SLIDESMANIA
ADDITION OF FRACTIONS
Mrs. Cruz bought
2
7
kg of minced meat on Monday and
another
4
7
kg on Tuesday. She mixed the meat together and
repacked. How much meat did she repack?
2
7
and
4
7
are fractions whose denominators are the same.
These fractions are called similar fractions. To add fractions,
simply put together like fraction or fractions with the same
denominator.
However, fractions with different denominators are called
dissimilar fractions.

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SLIDESMANIA
Similar Fractions
Example 1:
2
7
+
4
7
=
Since the denominators are the same, you can directly
add their numerators and copy the denominator.
2
7
+
4
7
=
𝟔
𝟕

8. SLIDESMANIA
SLIDESMANIA
Similar Fractions
Example 2:
To get the sum of a fraction with mixed number which are
similar, add whole number then add the corresponding
numerators over the same denominator.
2
5
+ 5
1
5
=
2
5
+ 5
1
5
= 𝟓
𝟑
𝟓

9. SLIDESMANIA
SLIDESMANIA
Similar Fractions
5
10
7
or 𝟔
𝟑
𝟕
3
4
7
+ 2
6
7
=
 In case the sum is a mixed
number whose fraction is an
improper fraction, change
the improper to mixed
number and add the
corresponding whole
numbers.

10. SLIDESMANIA
SLIDESMANIA
Similar Fractions
Example 3:
5
10
7
or 𝟔
𝟑
𝟕
3
4
7
+ 2
6
7
=
Add the given whole numbers and add also the numerators
over the same denominator.
3
4
7
+ 2
6
7
=
 In case the sum is a mixed number whose fraction is an
improper fraction, change the improper to mixed number
and add the corresponding whole numbers.

11. SLIDESMANIA
SLIDESMANIA
Similar Fractions
Example 4:
9 +
4
5
=
In adding a whole number by a fraction, just combine them to
become a mixed number.
9 +
4
5
= 𝟗
𝟒
𝟓

12. SLIDESMANIA
SLIDESMANIA
Similar Fractions
Example 5:
7
10
−
3
10
=
Since the denominators are the same, you can subtract
their numerators and copy the denominator, provided that the
difference must be in lowest term.
7
10
−
3
10
=
4
10
or
𝟐
𝟓

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SLIDESMANIA
Similar Fractions
Example 6:
3
2
5
−
1
5
=
To get the difference of a mixed number with a fraction, which
are similar, copy first the whole number then subtract the
corresponding numerators over the same denominator. Then, the
difference is,
3
2
5
−
1
5
= 𝟑
𝟏
𝟓

14. SLIDESMANIA
SLIDESMANIA
Similar Fractions
Example 7:
9 −
2
3
=
In subtracting a whole number by a fraction, rename the whole
number by borrowing 1 from the whole number and express 1 to
fraction whose numerator and denominator are the same as the
denominator of the other fraction.
8
3
3
−
2
3
=

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SLIDESMANIA
Copy the remaining whole number and
subtract the fractions as similar
fractions.
8
3
3
−
2
3
= 𝟖
𝟏
𝟑

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SLIDESMANIA
Dissimilar Fractions
Example 1: 3
4
+
2
3
=
Look for the least common denominator (LCD) of
the fractions. The LCD of
3
4
and
2
3
is 12.
Get the equivalent fractions.
3
4
=
𝟗
𝟏𝟐
and
2
3
=
𝟖
𝟏𝟐

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SLIDESMANIA
Since the denominators are now the same, you can
directly add their numerators and copy the
denominator.
9
12
+
8
12
=
𝟏𝟕
𝟏𝟐
Express the fraction to lowest term.
9
12
+
8
12
=
17
12
or 𝟏
𝟓
𝟏𝟐

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SLIDESMANIA
Example 2: 2
5
−
1
3
=
Look for the least common denominator (LCD) of the
fractions.
The LCD of
2
5
and
1
3
is 15.
Get the equivalent fractions.
2
5
=
𝟔
𝟏𝟓
and
1
3
=
𝟓
𝟏𝟓

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SLIDESMANIA
Since the denominators are now the
same, you can directly subtract their
numerators and copy the
denominator.
6
15
−
5
15
=
𝟏
𝟏𝟓

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SLIDESMANIA
Fractions
Example 3: 2
3
+ 5
1
2
=
 Convert the mixed fractions to improper fractions.
5
1
2
= 5 × 2 + 1 = 𝟏𝟏
5
1
2
=
𝟏𝟏
𝟐
 Then, get the LCD which is equal to 6.
2
3
=
𝟒
𝟔
and
11
2
=
𝟑𝟑
𝟔

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SLIDESMANIA
 Proceed to addition of similar fractions. That is,
4
6
+
33
6
=
37
6
 Express the sum whose fraction must be in lowest term.
2
3
+ 5
1
2
=
37
6
or 𝟔
𝟏
𝟔

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SLIDESMANIA
Dissimilar Fractions
Example 4:
3
1
3
− 1
2
7
=
 Look for the least common denominator (LCD) of the fractions.
The LCD of
1
3
and
2
7
is 21.
 Get the equivalent fractions.
1
3
=
𝟕
𝟐𝟏
and
2
7
=
𝟔
𝟐𝟏

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SLIDESMANIA
 Since the denominators are now the same, you can directly
subtract their whole numbers and numerators. Lastly, copy the
denominator.
3
7
21
− 1
6
21
= 2
1
21

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SLIDESMANIA
What are your
steps before going
to our school?

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SLIDESMANIA.C
Problem Solving
Involving Addition and
Subtraction of
Fractions

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SLIDESMANIA
Objectives
● Demonstrate understanding of
addition and subtraction of fractions,
● Solve the problems using addition
and subtraction, and
● Apply the steps in problem solving.

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SLIDESMANIA
Four steps to help solve
problem
1. Think
2. Plan
3. Solve
4. Look back

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SLIDESMANIA
Example
Jose weighs 115
1
4
pounds now due
to diet and exercise. Ten days
before, he weighed 150
1
2
pounds.
Did he gain or lose weight? By
how much?

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SLIDESMANIA
Think
What is the question?
Did Jose gain or lose weight? By how
much?
What are the facts?
Jose weighs 150
1
2
pounds before.
Jose weighs 115
1
4
pounds at present.

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SLIDESMANIA
Plan:
How can the answer be found?
By using subtraction
150
1
2
− 115
1
4
Solve:
Carry out the plan
150
1
2
− 115
1
4
= 150
2
4
− 115
1
4
= 35
1
4
𝑝𝑜𝑢𝑛𝑑𝑠.

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SLIDESMANIA
Look Back
Have you answered the question?
Is your arithmetic correct? Does
your answer make sense?
Therefore, Jose lost weight by
35
𝟏
𝟒
pounds

32. SLIDESMANIA
SLIDESMANIA
Sheila needs 9
3
4
meters of cloth fo her
gown. She has 1
1
3
meters of the cloth.
How many meters more does she need
to buy?
Think
Plan
Solve
Look Back

33. SLIDESMANIA
SLIDESMANIA
A carpenter was able to collect places of
wood with a length of 10
1
4
meters, 9
5
12
meters and 8
1
3
meters. How many meters of
wood does the carpenter have?
Think
Plan
Solve
Look back

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SLIDESMANIA

35. SLIDESMANIA
SLIDESMANIA

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SLIDESMANIA
Dissimilar Fractions
 Since the denominators are now the same, you can directly
subtract their whole numbers and numerators. Lastly, copy the
denominator.
3
7
21
− 1
6
21
= 2
1
21