## 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

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

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**

- GCD01 Divisors, Common Divisors, and Greatest Common Divisor
- GCD02 Finding the GCD of Two or More Numbers by Listing
- GCD03 Getting the GCD Using the Ladder Method
- GCD04 The Difference Between GCD and GCF
- GCD05 Finding the GCF by Prime Factorization (Without Exponents)
- GCD06 Finding the GCF by Prime Factorization (with Exponents)
- GCD07 Finding the GCF Using Factor Trees
- GCD08 Using GCD to Reduce Fractions to Lowest Terms

1.) Which of the following fractions is smaller than ?

a.)

b.)

c.)

d.)

2.) What is the value of 1.01 + 0.005 + .08?

a.) 1.14

b.) 1.095

c.) 2.4

d.) 1.0014

3.) Which of the following fractions is equivalent to 37.5%?

a.)

b.)

c.)

d.)

4.) In the sequences below, 36 and 72 are common numbers to both sequences.

Sequence 1: 12, 24, **36**, 48, 60, **72**…

Sequence 2: 18, **36**, 54,** 72…**

This is our second set of exercises on operations on decimals.

Perform the indicated operation.

1.) 1.5 + 0.7

2.) 10.5 + 3.08 + 4.026

3.) 0.8 – 0.2

4.) 8.06 – 3.215

5.) 5.7 – 0.9

6.) .22 × .6

7.) 5.02 × 1.2

8.) 8.1 ÷ 0.009

9.) .63 ÷ 30

10.) .7 ÷ .005

Add the following fractions.

1.)

2.)

3.)

4.)

5.)

6.)

7.)

8.)

9.)

10.)

Answer key and solution:

1.)

2.)

3.)

4.)

Solution:

Here are some Civil Service exam exercises on GCD and LCM.

1.) What is the GCD of 8, 20, and 28?

2.) What is the GCD of 21, 35, and 56?

3.) What is 18/54 in lowest terms?

4.) What is 38/95 in lowest terms?

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

6.) What is the LCM of 5, 6, and 12?

7.) What is the product of the LCM and the GCD of 4, 8, and 20?

8.) There are 18 red marbles and 27 blue marbles to be distributed among children. What is the maximum number of children that can receive the marbles if each kid receives the same number of marbles for each color and no marble is to be left over?

9.) In a school sportsfest, there are 60 Grade 4 pupils, 48 Grade 5 pupils and 36 Grade 6 pupils. What is the largest number of teams that can be formed if the pupils in each Grade level are equally distributed and no pupil is left without a team?

10.) In a disco, the red lights blink every 3 seconds and the blue lights blink every 5 seconds. If the two colored lights blink at the same time if you turn them on, they will blink at the same time every ___ seconds.