List the First Number's Multiples
Multiply the first number by 1, 2, 3, and so on to generate its multiples in order.
Free Interactive Math Tool
Least Common Multiple Practice
Generate multiples of two numbers, compare the completed lists, identify the first number that appears in both, and find the least common multiple step by step.
Learn How to Compare Multiples First
Learn what multiples are, how to generate them in order, how to identify common multiples, and why the first common multiple is the least common multiple.
Read the Least Common Multiple GuideHow It Works
Find the LCM by Listing Multiples
Generate the multiples of both numbers in order, compare the completed lists, and choose the smallest value that appears in both.
List the Second Number's Multiples
Build a second ordered list using the same repeated-multiplication process.
Find the First Match
Compare the two lists and select the first value that appears in both.
Interactive Practice
Least Common Multiple
Correct
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Problems
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Streak
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Find the least common multiple of
12
18
List the multiples of both numbers, compare the completed lists, and identify the smallest value that appears in both.
1
First List
2
Second List
3
First Match
Step 1
List the multiples of the first number.
Multiply 12 by 1, 2, 3, and so on. Enter the multiples in order from least to greatest.
First Number
12
Enter six multiples. Use Tab or Enter to move to the next box.
Step 2
List the multiples of the second number.
Multiply 18 by 1, 2, 3, and so on. Enter the multiples in order from least to greatest.
Second Number
18
Enter six multiples. Use Tab or Enter to move to the next box.
Step 3
Select the first common multiple.
Compare both completed lists. Select the smallest value that appears in both lists.
Multiples of 12
Multiples of 18
Selected Common Multiple
Excellent!
You correctly found the least common multiple.
Helpful Reminders
Tips for Finding the Least Common Multiple
Keep Multiples in Order
Start with the number times 1, then times 2, times 3, and continue in order.
Compare Both Lists
A common multiple must appear in the multiples list for both original numbers.
Choose the Smallest Match
There may be several common multiples, but the least common multiple is the first one.
Check Both Divisions
The LCM should divide evenly by both original numbers.
Why Learn This?
Where You'll Use the LCM
Adding Fractions
Use the LCM of the denominators to find the least common denominator.
Repeating Schedules
The LCM tells you when two repeating events will happen together again.
Patterns and Cycles
Compare repeating numerical patterns and identify their first shared value.
Keep Practicing
Generate new number pairs, build their multiples in order, and practice identifying the first common multiple with immediate feedback.