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Math - Class 4 – Addition of Unlike Fractions/Adding Fractions with Unlike Denominators/Add Fractions with Different Denominators - Key Points/Notes/Worksheets/Explanation/Lesson/Practice Questions Tags: Free downloadable Worksheet PDF on Addition of unlike fractions for class 4, Add fractions with unlike denominators for fourth Grade, How do you add two fractions with different denominators? Lesson on Addition of unlike fractions for 4rth standard , How do you add fractions together? Adding unlike fraction for class IV, Quiz on unlike fractions, Steps to add unlike fractions, How to add unlike fraction.
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Addition of Unlike Fractions
Step 1: Use LCM method to convert the unlike fractions into like fractions.
Step 2: Find out new numerators of the given fractions.
Step 3: Add new numerators.
Step 4: Write the resulting numerator after addition over the LCM as denominator.
Step 5: If resultant fraction is an improper fraction then convert it into mixed fraction.
Example 1:
Here denominators are different. So, we will first make denominators of the given fractions equal, using LCM method.
LCM OF 3 and 4
= 3 x 4
= 12
Now we have to find out new numerators of the both fractions.
New Numerator of the first fraction =
LCM ÷ Denominator of the first fraction x Numerator of the first fraction
= 12 ÷ 3 = 4 (LCM ÷ Denominator of the first fraction)
= 4 x 1 =4 (Resultant answer x Numerator of the first fraction)
New numerator of first fraction is 4
New Numerator of the second fraction =
LCM ÷ Denominator of the second fraction x Numerator of the second fraction
= 12 ÷ 4 = 3 (LCM ÷ Denominator of the second fraction)
= 3 x 1 =3 (Resultant answer x Numerator of the second fraction)
New numerator of second fraction is 3
Now add new numerators
= 4 + 3
= 7
Then write the resulting numerator after addition over the LCM as denominator.
Example 2:
Here denominators are different. So, we will first make denominators of the given fractions equal, using LCM method.
LCM OF 7, 21 and 14
7
7, 21, 14
2
1, 3 , 2
3
1, 3, 1
1, 1, 1
= 7 x 2 x 3
= 42
Now we have to find out new numerators of the all the fractions.
New Numerator of the first fraction =
LCM ÷ Denominator of the first fraction x Numerator of the first fraction
= 42 ÷ 7 = 6 (LCM ÷ Denominator of the first fraction)
= 6 x 4 = 24 (Resultant answer x Numerator of the first fraction)
New numerator of first fraction is 24
New Numerator of the second fraction =
LCM ÷ Denominator of the second fraction x Numerator of the second fraction
= 42 ÷ 21 = 2 (LCM ÷ Denominator of the second fraction)
= 2x2 =4 (Resultant answer x Numerator of the second fraction)
New numerator of second fraction is 4
New Numerator of the third fraction =
LCM ÷ Denominator of the third fraction x Numerator of the third fraction
= 42 ÷ 14 = 3 (LCM ÷ Denominator of the third fraction)
= 3x31 =93 (Resultant answer x Numerator of the third fraction)
New numerator of third fraction is 93
Now add all new numerators
= 24 + 4 + 93
= 121
Then write the resulting numerator after addition over the LCM as denominator.
Now convert the improper fraction into mixed fraction
Note:
1. In addition of a whole number and a fractional number, we assume denominator of whole number as 1 for calculation.
2. In addition of mixed fractions, convert mixed fraction into improper fraction before starting to add.
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