Barstow Community College Finding the Least Common Multiple Discussion.

### Question Description

This discussion has two parts:

1. __ Discuss and explain__ how you would go about finding the Least Common Denominator of a set of numbers and

__. (17 points)__

**provide an example where you find the least common denominator between two numbers**2. Reply to all of your classmates’ posts, providing questions, suggestions, help, and enough feedback to elaborate on your post/reply. ( 8 points)

—————————————————————- respond to these posts———-

Tiffany,

Example: What is 1/6 + 7/15The Denominators

The Denominators are 6 and 15:

Then the **Least Common Multiple** of 6 and 15 is **30**.

Multiples of 6: 6,12,18,24,**30**,36, …

Multiples of 15: 15, **30**, 45, 60, …

Now let’s try to make the denominators the same.

Note: what we do to the bottom of the fraction,

we must also do to the top

For the first fraction we can multiply top and bottom by 5 to get a denominator of 30:

1 multiply 5 = 5

6 multiply 5 = 30

**1/6 = 5/30**

For the second fraction we can multiply top and bottom by 2 to get a denominator of 30:

7 multiply 2 = 14

15 multiply 2 = 30

**7/15 = 14/30**

Now we can do the addition by adding the top numbers:

**5/30 + 14/30**

The fraction is already as simple as it can be, so that is the answer.

**= 19/30**

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Carlo,

Hello Professor and Classmates,

To find the Least Common Denominator or LCD of two sets of numbers, we have to find their prime numbers.

My example:

3 6 + 2 15

The denominators are 6 and 15. Now their LCD

6 = 2 ? 3

15 = 3 ? 5

Now bring the numbers down, 3 occurs on both numbers, so let us only write one of them, 2,3,5 and then multiply them to each other and you will get 2 ? 3 ? 5 = 30 .

Now 3 6 + 2 15 , becomes, 3 30 + 2 30

Next step, let us add the numerators 3 + 2 = 5 , and bring down the LCD which will give us , 5 30 . We can factor 5 out of both 5 and 30, how many 5s we get from 5 is 1, and how many 5s we get from 30 is 6, now lets rewrite it, and this will give us the answer of 1 6 .

This is my understanding. Please feel free to correct me if I’m wrong, thank you.

Barstow Community College Finding the Least Common Multiple Discussion