subtraction of fractions Archives - PH Civil Service Exam Reviewer

Subtraction of Fractions Exercises – Set 1

By Civil Service Reviewer
on Apr 28, 2017
in Mathematics

Find the difference of the following:

1.) $\dfrac{8}{11} - \dfrac{3}{11}$

2.) $\dfrac{7}{16} - \dfrac{3}{16}$

3.) $\dfrac{4}{5} - \dfrac{3}{4}$

4.) $7 - \dfrac{4}{9}$

5.) $8 \dfrac{9}{10} - \dfrac{3}{10}$

6.) $6 \dfrac{2}{7} - \dfrac{5}{7}$

7.) $4 \dfrac{1}{3} - \dfrac{1}{6}$

8.) $6 \dfrac{3}{5} - 2 \dfrac{3}{4}$

9.) $11 \dfrac{2}{3} - 7$

10.) $9 \dfrac{2}{5} - \dfrac{11}{9}$

Answers:

1.) $\dfrac{5}{11}$

2.) $\dfrac{1}{4}$

Solution
$\dfrac{7}{16} - \dfrac{3}{6} = \dfrac{4}{16} = \dfrac{1}{4}$

3.) $\dfrac{1}{20}$

Solution
LCD: 20
$\dfrac{4}{5} - \dfrac{3}{4} = \dfrac{16}{20} - \dfrac{15}{20} = \dfrac{1}{20}$

4.) $6 \dfrac{5}{9}$

Solution

We can decompose 7 into 6 and 9/9.

$6 \dfrac{9}{9} - \dfrac{4}{9} = 6 \dfrac{5}{9}$

5.) $8 \dfrac{3}{5}$

Solution
$8 \dfrac{9}{10} - \dfrac{3}{10} = 8 \dfrac{6}{10} = 8 \dfrac{3}{5}$

6.) $5 \dfrac{4}{7}$

Solution
$5 \dfrac{9}{7} - \dfrac{5}{7} = 5 \dfrac{4}{7}$

7.) $4 \dfrac{1}{6}$

Solution
LCD: 6
$4 \dfrac{1}{3} - \dfrac{1}{6} = 4 \dfrac{2}{6} - \dfrac{1}{6} = 4 \dfrac{1}{6}$

8.) $3 \dfrac{17}{20}$

Solution
LCD: 20
$5 \dfrac{8}{5} - 2 \dfrac{3}{4} = 5 \dfrac{32}{20} - 2 \dfrac{15}{20} = 3 \dfrac{17}{20}$

9.) $4 \dfrac{2}{3}$

Solution
$11 \dfrac{2}{3} - 7 = 4 \dfrac{2}{3}$

10.) $8 \dfrac{8}{45}$

Solution
$9 \dfrac{2}{5} - \dfrac{11}{9} = 8 \dfrac{7}{5} - \dfrac{11}{9}$

LCD: 45
$8 \dfrac{63}{45} - \dfrac{55}{45} = 8 \dfrac{8}{45}$

PCSR REVIEW SERIES WEEK 3: Addition and Subtraction of Fractions

Last week, we have learned how to add and subtract fractions. In this post, we are going to learn about addition of mixed fractions.

There are two strategies in addition and subtraction of mixed fractions. The first one is to add or subtract first the whole numbers (if possible), then add or subtract the fraction. The second is to convert the mixed fractions to improper fractions before performing addition or subtraction.

The following are the Youtube videos where you can learn how to add and subtract mixed fractions.

If you have time, I suggest that you watch the complete FRACTION SERIES here (24 videos):

Good luck!

Subtraction of Fraction Quiz 1

By Civil Service Reviewer
on Apr 28, 2014
in Mathematics

This is the first quiz in the series of quizzes on subtraction of fractions. If you have forgotten or have not learned subtraction of fractions yet, you can read How to Subtract Fractions, take the practice test, and see if your solutions and answers are correct.

In the quiz below, the answer is revealed after you answer each question. Correct answers are highlighted with green color. In case you made a mistake, your answer will be highlighted red.

[WpProQuiz 8]

A Summary of the Operations on Fractions Series

Fractions is one of the concepts that you should master if you want to pass the Civil Service Examination. Although fraction seems like a simple context, most of the time it is used in higher mathematics such as algebraic manipulation as well as in problem solving. We have discussed all the operations in fractions, but notice that I first discussed multiplication and division before addition and subtraction. This is because the first two operations are easier. I recommend that you read the series the order that I have written it.

Operations on Fractions Series

In addition, I am also planning to write 3 to 4 more articles to discuss more complex problems, but not immediately. I will be switching my discussions on decimals and percents and then proceed to Algebra and word problem solving soon. I will also be discussing other types of exams in English.

The next Civil Service Examination is in April 2014. I strongly suggest that you start reviewing now if you are planning to take the test.

Tagalog Video: The Concept of Least Common Multiple

By Civil Service Reviewer
on Jan 06, 2014
in Mathematics, Taglish Math Videos, Tutorials

I am planning to include videos of explanation of mathematical concepts in this blog and below is my first trial video. The explanation in the video is mostly Filipino (Tagalog) and sometimes English. This video discusses the concept of least common multiple which is used in addition of fractions.

I hope you learn something from here. Please feel free to use the comment box. 🙂

Note: In 4:49, I said that the fraction will become larger. Actually, the value of the fraction does not change. It is the number in the numerator and the denominator that becomes larger.

Practice Test on Subtraction of Fractions

By Civil Service Reviewer
on Dec 16, 2013
in Mathematics, Practice Tests, Tutorials

A month ago, I have discussed the first part of the subtraction of fraction tutorials and I apologize for the delay of the exercises. Sharpen what you have learned from the practice test below.

Practice Test on Subtraction of Fractions

1. $\frac{13}{17} - \frac{2}{17}$ .

2. $\frac{8}{15} - \frac{4}{15}$ .

3. $\frac{5}{8} - \frac{1}{2}$

4. $\frac{4}{5} - \frac{1}{3}$

5. $2 \frac{3}{5} - \frac{1}{4}$

6. $4 \frac{5}{6} - 2 \frac{1}{6}$ Continue Reading

How to Subtract Fractions

We have already learned the three operations on fractions namely addition, multiplication, and division. In this post, we are going to learn the last elementary operation: subtraction. If you have mastered addition of fractions, this will not be a problem for you because the process is just the same. Let’s subtract fractions!

Example 1: $\displaystyle \frac{8}{15} - \frac{3}{15}$ .

Solution

The given is a similar fraction (fraction whose denominators are the same), so just like in addition, we just perform the operation on the numerators. Therefore, we just have to subtract the numerator and copy the denominator. That is, Continue Reading

How to Get the Least Common Multiple of Numbers

In mathematics, a multiple is a product of any number and an integer. The numbers 16, -48 and 72 are multiples of 8 because 8 x 2 = 16, 8 x -3 = -48 and 8 x 9 = 72. Similarly, the first five positive multiples of 7 are the following:

7, 14, 21, 28, 35.

In this post, we will particularly talk about positive integers and positive multiples. This is in preparation for the discussions on addition and subtraction of fractions.

We can always find a common multiple given two or more numbers. For example, if we list all the positive multiples of 2 and 3, we have

2, 4, 6, 8, 10, 12, 14, 16, 18, 20

and

3, 6, 9, 12, 15, 18, 21, 24, 27, 30. Continue Reading

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