Understanding Least Common Multiple (LCM)

Understanding Least Common Multiple (LCM)

Assessment

Interactive Video

Mathematics

5th - 8th Grade

Practice Problem

Hard

Created by

Ethan Morris

FREE Resource

This video tutorial explains how to find the least common multiple (LCM) of a set of numbers. It begins by defining LCM and demonstrates the process using examples with numbers 6 and 10, and then 5 and 8. The video emphasizes listing multiples to find the smallest common one, warning against shortcuts like multiplying the numbers directly, which may not yield the LCM. The tutorial concludes with a reminder that the listing method is more reliable, especially for larger numbers.

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8 questions

Show all answers

1.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the Least Common Multiple (LCM) of a set of numbers?

The sum of all the numbers in the set.

The smallest number that is a multiple of all the numbers in the set.

The difference between the largest and smallest numbers in the set.

The largest number that divides all the numbers in the set.

2.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the first step in finding the LCM of two numbers?

Divide the larger number by the smaller number.

List the multiples of each number.

Multiply the two numbers.

Add the two numbers.

3.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

When finding the LCM of 6 and 10, which number is the first common multiple?

12

60

24

30

4.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

Which of the following is a common multiple of 6 and 10?

30

20

18

40

5.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

Why is multiplying the numbers not a reliable method to find the LCM?

It is a faster method but less accurate.

It only works for even numbers.

It sometimes gives a common multiple but not the smallest one.

It always gives the smallest common multiple.

6.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the LCM of 5 and 8?

20

50

30

40

7.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is a potential downside of listing multiples to find the LCM?

It requires a calculator.

It is not accurate.

It can be time-consuming for large numbers.

It only works for prime numbers.

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