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Grade 6 Math · Least Common Multiple

Grade 6 Least Common Multiple Practice Test

Build Grade 6 Math skills with five 10-question practice tests on multiples, prime factorization, least common multiple, repeating schedules, and synchronization problems.

Least Common Multiple Practice Tests

These Grade 6 Math practice tests help students find the smallest positive multiple shared by two or more numbers. Students practice listing multiples, prime factorization, repeating schedules, synchronization, common denominators, and real-world timing problems involving lights, buses, reminders, machines, and events.

Skills covered

  • Listing multiples and identifying common multiples
  • Finding the least common multiple by lists and prime factorization
  • Using the greatest exponent of each prime factor
  • Distinguishing LCM from GCF and factors from multiples
  • Checking whether a proposed value is the least positive common multiple
  • Solving repeating-event and synchronization problems
  • Connecting LCM reasoning to common denominators and real-world schedules

How to use these practice tests

List the first few multiples when the numbers are small. For larger numbers, write prime factorizations and use every prime with the greatest exponent appearing in any factorization. In schedule problems, identify the first time or step when all repeating events occur together and verify it by division.

For more Grade 6 Math practice, return to the Grade 6 Math category.

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Grade 6 Least Common Multiple Practice Tests

A 10-question Grade 6 Math practice test on multiples, common multiples, prime factorization, least common multiple, schedules, and synchronization problems.

List multiples or use prime factorization, identify the first positive shared multiple, and check that it is divisible by every number.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

One light flashes every 4 seconds and another every 6 seconds. After how many seconds will they flash together again?

Please select an answer first.

Correct answer: A

The correct answer is 1212.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: The next shared flash occurs at LCM(4,6)=12LCM(4,6) = 12 seconds.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

The next shared flash occurs at LCM(4,6)=12LCM(4,6) = 12 seconds.

2. QuestionMultiple choice

A bus arrives every 8 minutes and another every 12 minutes. When will they arrive together again?

Please select an answer first.

Correct answer: B

The correct answer is 2424 minutes.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(8,12)=24LCM(8,12) = 24 minutes.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(8,12)=24LCM(8,12) = 24 minutes.

3. QuestionMultiple choice

Two bells ring every 5 minutes and every 7 minutes. When will they ring together again?

Please select an answer first.

Correct answer: C

The correct answer is 3535 minutes.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: The first shared ringing time is LCM(5,7)=35LCM(5,7) = 35 minutes.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

The first shared ringing time is LCM(5,7)=35LCM(5,7) = 35 minutes.

4. QuestionMultiple choice

A student practices scales every 3 days and reading every 4 days. After how many days will both happen on the same day again?

Please select an answer first.

Correct answer: D

The correct answer is 1212 days.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(3,4)=12LCM(3,4) = 12 days.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(3,4)=12LCM(3,4) = 12 days.

5. QuestionMultiple choice

A plant is watered every 6 days and fertilized every 10 days. After how many days will both tasks occur together?

Please select an answer first.

Correct answer: A

The correct answer is 3030 days.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(6,10)=30LCM(6,10) = 30 days.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(6,10)=30LCM(6,10) = 30 days.

6. QuestionMultiple choice

One alarm sounds every 9 minutes and another every 15 minutes. When will they sound together?

Please select an answer first.

Correct answer: B

The correct answer is 4545 minutes.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(9,15)=45LCM(9,15) = 45 minutes.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(9,15)=45LCM(9,15) = 45 minutes.

7. QuestionMultiple choice

Two machines complete a cycle every 12 and 18 minutes. When do their cycles align?

Please select an answer first.

Correct answer: C

The correct answer is 3636 minutes.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(12,18)=36LCM(12,18) = 36 minutes.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(12,18)=36LCM(12,18) = 36 minutes.

8. QuestionMultiple choice

Two events repeat every 14 days and every 20 days. After how many days will they repeat together?

Please select an answer first.

Correct answer: D

The correct answer is 140140 days.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(14,20)=140LCM(14,20) = 140 days.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(14,20)=140LCM(14,20) = 140 days.

9. QuestionMultiple choice

One medicine is taken every 2 hours and another every 3 hours. When are both taken together again?

Please select an answer first.

Correct answer: A

The correct answer is 66 hours.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(2,3)=6LCM(2,3) = 6 hours.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(2,3)=6LCM(2,3) = 6 hours.

10. QuestionMultiple choice

Two wheels complete a marked rotation every 16 and 24 seconds. When will the marks align again?

Please select an answer first.

Correct answer: B

The correct answer is 4848 seconds.

  1. List the multiples: Write multiples of each number or use prime factorization.
  2. Find the first shared multiple: LCM(16,24)=48LCM(16,24) = 48 seconds.
  3. Check the result: Verify that the answer is divisible by every number and that no smaller positive common multiple works.

LCM(16,24)=48LCM(16,24) = 48 seconds.

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Frequently asked questions about Grade 6 Least Common Multiple

What topics are covered?

The page covers multiples, common multiples, prime factorization, least common multiple, GCF versus LCM, repeating schedules, synchronization, and common-denominator connections.

When is the LCM useful?

The LCM is useful when repeating events must be aligned, when schedules synchronize, or when a common denominator is needed for fractions.

How many questions are on this page?

The page includes five mini tests with 10 questions each, for 50 Grade 6 Least Common Multiple questions in total.