## GCD Practice Exercises with Solutions on Youtube

Find the GCD/GCF of the following numbers.

1. 12, 18
2. 14, 35
3. 20,28
4. 25, 30, 40
5. 7, 12
6. 48, 72
7. 42, 60, 72
8. 24, 36
9. 12, 16
10. 18, 30, 54

## Review for August 2019 has already started

After a one-month break, we have already started our review series for the month of August 2019. The date of the examination will be on August 7, 2019. If you wish to follow our review series (I suggest you do), please like and then follow the Philippine Civil  Service Exam Reviewer Facebook page. Every week, we post Math, English, and Clerical tutorials and practice questions. For the first week our topics are LCM, GCD, Subject Verb agreement. You may download the review outline here.

We have already posted new video tutorials in Filipino on LCM and GCD on the Sipnayan Youtube channel.

Greatest Common Divisor/Greatest Common Factor

## 2018 PCSR Civil Service Review Guide 1

Week 1: September 24 – October 1, 2017

This week, we are going to learn about Least Common Multiple (LCM) and Greatest Common Divisor (GCD). LCM is needed in adding and subtracting dissimilar fractions, while GCD is needed in reducing fractions to lowest terms. In addition to LCM and GCD, we will also learn about converting improper fractions to mixed number and vice versa.

PART I: MATHEMATICS

A. GCD

Lesson 1: Understanding Common Divisors
Lesson 2: Common Divisors and Greatest Common Divisor
Lesson 3: Exercises on Getting the GCD
Lesson 4: Getting the GCD by Prime Factorization
Lesson 5: GCD and Reducing Fractions to Lowest Terms

Tutorial Articles

B. LCM

Lesson 1: Least Common Multiple Part 1
Lesson 2: Least Common Multiple Part 2
Lesson 3: Least Common Multiple Part 3

Tutorial Article

How to Get the Least Common Multiple of Numbers

C. Lowest Terms, Improper Fractions and Mixed Form

Tutorial Articles

D. More about LCM and GCD

Difference between LCM and GCD

PART II: ENGLISH

A. Vocabulary

Civil Service Exam Vocabulary Review Part 1

B. Grammar
Lesson 1: Verb and Tenses: An Introduction
Lesson 2: The Subject-Verb Agreement Rules Part 1
Lesson 3: The Subject-Verb Agreement Rules Part 2
Lesson 4: Subject-Verb Agreement Exercise

C. Spelling

Civil Service Review Spelling Quiz 1 Set 2

Part III: CLERICAL (Subprofessional)

PART III: TIPS AND TRICKS

MORE REVIEWERS

1. Math English Tutorials and more at the PCSR Civil Service Review website:

http://civilservicereview.com

2. More than 700 Taglish Math Tutorials at the Sipnayan Youtube channel:

3. Sipnayan Website

http://sipnayan.com

Like our Facebook Pages and be updated:

## LCM and GCD Exercises Set 1

After learning about LCM and GCD in our PCSR Review Guide 1, let’s practice what we have learned by answering the exercises below.

1.) What is the LCM of 6 and 8?

2.) What is the LCM of 3, 4, and 9?

3.) Consider the following sequences:
Sequence 1: 4, 8, 12, 16, 20, 24, 28, …
Sequence 2: 5, 10, 15, 20, 25, 30, …
As we can see, 20 is common to both sequences. What is the 10th common number?

4.) Gina goes to BODY SLIM gym every 3 days, while Sam goes to the same gym every 4 days. If they were in the same gym on a February 12, what’s the nearest date that they will be both in the gym?

5.) In a decoration LED light, the green lights blink every 400 milliseconds, the blue light every 500 milliseconds, and the red light every 750 milliseconds. If the three lights all blinked at the same time, in how many milliseconds will they again blink at the same time?

6.) What is the LCD of 1/3, 1/4, and 1/6?

7.) What is the GCD of 28 and 35?

8.) What is the GCD of 39, 65, and 91?

9.) A rectangular paper with dimensions 12 inches by 18 inches is to be cut into largest possible squares of equal sizes. If no paper is to be wasted, what should be the dimensions of the squares?

Q10.) A rectangular prism piece of wood with dimensions 16 inches by 20 inches by 32 is to be cut into cubes of the same size.

A. If we want to minimize the wasted wood while cutting, what should be the dimensions of the cubes?

B. How many cubes can we make given the above conditions?

1.) 24

2.) 36

3.)  200

4.) LCM of 3 and 4 is 12. Twelve days after February 12 is February 24.

5.) 6000 milliseconds

6.) 12

7.) 7

8.) 13

9.) Side of the square should be GCD of 12 and 18 which is 6 inches.

10.) A. Side of the cube should be GCD of 16, 20, and 32 which is equal to 4 inches.

B. 16/4 × 20/4× 32/4 = 4 × 5 × 8 = 160 cubes

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## PCSR Civil Service Exam Review Guide 14

After learning work problems, we now learn how to answer mixture problems.

PART I: MATH

B. Articles

Part II: ENGLISH
Civil Service Exam Vocabulary Review 13

## PCSR Civil Service Exam Review Guide 11

After learning age problems in PCSR Review Guide 10, let us now learn motion problems. Motion problems are problems that deal with distance, rate, and time. Watch the videos below and read the articles. From Wednesday to Saturday this week, I will post 10-15 practice problems.

PART I: MATH
A. Videos

B. Articles

Part II: ENGLISH

A. Vocabulary

Civil Service Exam Vocabulary Review 10

B. Grammar

## PCSR Civil Service Exam Review Guide 10

After learning how to solve number problems, let’s learn how to solve age problems. Watch the videos below and read the articles. Then, we will have exercise later.

PART I: MATH

A. Videos (These videos are in Taglish and the links point to Youtube).

B. Articles

C. Exercises

Part II ENGLISH

A. Vocabulary

Civil Service Exam Vocabulary Review 9

For those who are searching the Review Guides 1 to 9, you can find them here.

## PCSR Civil Service Exam Review Guide 9

PART I: MATH

A. Youtube Videos (All videos are in Taglish)

How to Solve Number Problems Mentally

How to Solve Word Number Problems

How to Solve Consecutive Number Problems

B. Articles. You can read the articles below.

How to Solve Number Word Problems

How to Solve Consecutive Number Problems

Part II ENGLISH

A. Vocabulary

Civil Service Exam Vocabulary Review 8

B. Grammar and Correct Usage