1. Fraction IX Least Common Multiple Least Common Denominator
By Monica Yuskaitis

2. To Add or Subtract Fractions With Unlike Denominators
Find the multiples of each denominator. 1 5
= 5, 10, 15, 20, 25, 30 1 + 10
= 10, 20, 30, 40, 50

3. To Add or Subtract Fractions With Unlike Denominators
Compare the lists of multiples. Circle the common multiples between the two lists. 1
5 = 5, 10, 15, 20, 25, 30 1 +
10 = 10, 20, 30, 40, 50

4. To Add or Subtract Fractions With Unlike Denominators
Use the lowest common multiple as the denominator. 1
5 = 5, 10, 15 ,20 ,25 ,30 1 +
10 = 10, 20, 30, 40, 50

5. To Add or Subtract Fractions With Unlike Denominators
This number is also called the least common denominator. 1
5 = 5, 10, 15 ,20 ,25 ,30 1 +
10 = 10, 20, 30, 40, 50

6. Find the Least Common Denominator or Least Common Multiple1
2 = 2, 4, 6, 8, 10, 12 1 +
8 = 8, 16, 24, 32, 40

7. Find the Least Common Denominator or Least Common Multiple1
10 = 10, 20, 30, 40, 1 +
8 = 8, 16, 24, 32, 40

8. Find the Least Common Denominator or Least Common Multiple1
10 = 10, 20, 30, 40, 1 +
4 = 4, 8, 12, 16, 20,

9. Find the Least Common Denominator or Least Common Multiple1
2 = 2, 4, 6, 8, 10, 1 +
4 = 4, 8, 12, 16, 20,

10. Find the Least Common Denominator or Least Common Multiple1
2 = 2, 4, 6, 8, 10, 12 1 +
12 = 12, 24, 36, 48

11. Find the Least Common Denominator or Least Common Multiple1
3 = 3, 6, 9, 12, 15 1 +
4 = 4, 8, 12, 16, 20,

12. Find the Least Common Denominator or Least Common Multiple1
3 = 3, 6, 9, 12, 15 1 +
5 = 5, 10, 15, 20, 25,

13. Find the Least Common Denominator or Least Common Multiple1
3 = 3, 6, 9, 12, 15 1 +
9 = 9, 18, 27, 36, 45,

14. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Check to see if the smaller denominator
divides evenly into the larger denominator.
If it does, use the larger denominator for
your LCD or LCM. 1
3 will divide evenly into 9,
so 9 is your LCD or LCM. 3 1 + 9

15. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
2 will divide evenly into 4,
so 4 is your LCD or LCM. 2 1 + 4

16. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
2 will divide evenly into 10,
so 10 is your LCD or LCM. 2 1 + 10

17. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
2 will divide evenly into 12,
so 12 is your LCD or LCM. 2 1 + 12

18. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
4 will divide evenly into 8,
so 8 is your LCD or LCM. 4 1 + 8

19. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
3 will divide evenly into 6,
so 6 is your LCD or LCM. 3 1 + 6

20. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
3 will divide evenly into 12,
so 12 is your LCD or LCM. 3 1 + 12

21. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
3 will divide evenly into 15,
so 15 is your LCD or LCM. 3 1 + 15

22. Shortcut for Finding the Least Common Denominator or Least Common Multiple
Using the shortcut, what is the LCD or
LCM? 1
3 will not divide evenly into
8, so find the least common
multiple. 3 1 + 8