1. Objective - To find the Least Common Multiple (LCM) of numerical and variable expressions and use it to compare and order fractions. Smallest number that a set of given numbers divides evenly into (the first number that appears in both of the times tables for the numbers. LCM -Least Common Multiple - Three ways to find the LCM 1) Make a list of multiples. 2) Use the prime factorizations 3) Use Upside-down Division

2. Make a List of Multiples 1) Find the LCM of 10 and 12. 2) Find the LCM of 32 and 40. 10:10, 20, 30, 40, 50, 60, 70, 80, 90, 100 12:12, 24, 36, 48, 60 LCM = 60 32:32, 64, 96, 128, 160, 192, 224, 256 40:40, 80, 120, 160 LCM = 160...

3. Use prime factorization to find the LCM. 20 2 10 2 5 18 2 9 3 3 Select all common factors once. Then select the remaining factors.

4. Use prime factorization to find the LCM. 45 5 9 3 3 Select all common factors once. Then select the remaining factors. 72 8 9 3 3 2 4 2 2

5. Using Upside-Down Division to Find the LCM Find the LCM of 48 and 80. 48 80 8 6 10 2 3 5 Common Factors Once Remaining Factors

6. Using Upside-Down Division to Find the LCM Find the LCM of 90 and 120. 90 120 30 3 4 Common Factors Once Remaining Factors

7. Common Factors Once Using Upside-Down Division to Find the LCM Remember to take every variable to the highest power