Download Methods to Finding LCM Method 1: Use a list

Methods to Finding LCM
Method 1: Use a list
1. List several multiples of each number.
2. Find the smallest multiple the numbers have in common.
3. If you cannot find an LCM, continue listing the multiples.
Ex 1:
3: 3, 6, 9, 12, 15 LCM = 15
5: 5, 10, 15, 20, 25
Method 2: L Shape
1.
Make an L shape and put both numbers inside.
12
15
2. Find a number that evenly divides into both numbers. Place this number on the left side
of the L.
3
3.
4.
5.
12
15
Divide the number and place the solutions under the L shape.
3
12
15
4
5
Repeat steps 2-3 if the numbers still have a common factor.
Multiply all the numbers that are outside of the L shape. The product is the LCM.
3 x 4 x 5 = 60
**The LCM of 12 and 15 is 60.**
Find the LCM of the following numbers using this method.
1. 6 and 8
2. 8 and 12
3. 10 and 15
Method 3: Use Venn diagrams
1. Write the prime factorization of each number.
2. List the common prime factors in the center of the circles.
3. List the remaining prime factors in the outside circles.
4. Multiply all the prime factors to get the LCM.
More Practice:
1. Find the LCM of 10 and 15.
2. Find the LCM of 14 and 12.
3. Find the LCM of 8 and 6.
4. Find the LCM of 8 and 12.
5. Find the LCM of 9 and 15.
6. Find the LCM of 16 and 12.Find the LCM of 24 and 36.
7. Find the LCM of 21 and 63.