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More Lessons for Arithmetic

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The following diagrams show how to find the Least Common Multiple (LCM): by Listing out the Multiple, by using Prime Factorization, by using Repeated Division. Scroll down the page for examples and solutions.

### Repetitive Division

**Least Common Multiple (LCM)**

Find the LCM by listing the multiples of each number and find the smallest one that is common.

Another method is to use prime factorization.

Example:

What is the least common multiple (lcm) of 15, 6, and 10?

**How to obtain the least common multiple using the repetitive division method?**

Example:

Finding the LCM of 3 or more numbers

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

More Lessons for Arithmetic

Math Worksheets

The smallest number among the common multiples of two or more numbers is called their **least common multiple ** (LCM).

* Example: *

Find the LCM of 2, 3 and 6.

* Solution: *

Multiples of 2: 2, 4, **6**, 8, 10, **12**, 14, 16, **18**, ...

Multiples of 3: 3, **6**, 9, **12**, 15, **18**, ...

Multiples of6: **6**, **12**, **18**, ...

The common multiples are 6, 12, 18, ...

The smallest among them is 6.

Therefore, the Least Common Multiple (LCM) is 6.

Using the lists to find the LCM can be slow and tedious. A faster way is to use **repetitive division** to find the least common multiple.

Divide the numbers by prime numbers. If a number cannot be divided it is copied down to the next step of division.

For example, to find the LCM of 3, 6 and 9, we divide them by any factor of the numbers in the following manner:

Find the LCM by listing the multiples of each number and find the smallest one that is common.

Another method is to use prime factorization.

Example:

What is the least common multiple (lcm) of 15, 6, and 10?

Example:

Finding the LCM of 3 or more numbers

Rotate to landscape screen format on a mobile phone or small tablet to use the **Mathway** widget, a free math problem solver that **answers your questions with step-by-step explanations**.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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