This document provides examples for adding and subtracting fractions with unlike denominators. It explains that to add fractions with different denominators, you must first find the least common denominator and convert the fractions so they have the same denominator. Then you can simply add the numerators and keep the common denominator. Subtraction follows the same process. Several word problems are worked through step-by-step as examples.

1. Adding & Subtracting Fractions with unlike denominators 12/8/09 EQ: How do I add & subtract fractions when the denominator is different? 12/8/2009 1 Bitsy Griffin Lessons 2-24 & 25

2. Review: How do you add fractions with the same denominator? 12/8/2009 2 Bitsy Griffin Lessons 2-24 & 25

3. Problem 1: Eleni ate ¼ box of cereal. Freddie ate 3/8 box of the same box of cereal. 12/8/2009 3 Bitsy Griffin Lessons 2-24 & 25

4. Problem 1: What portion of the box did they eat in all? 12/8/2009 4 Bitsy Griffin Lessons 2-24 & 25

5. Problem 1: What needs to happen to add these 2 fractions? Need same denominator. 12/8/2009 5 Bitsy Griffin Lessons 2-24 & 25

6. Problem 1: Need same denominator. Least Common Denominator LCD 12/8/2009 6 Bitsy Griffin Lessons 2-24 & 25

7. Problem 1: How can we get the same denominator? ¼ = 2/8 12/8/2009 7 Bitsy Griffin Lessons 2-24 & 25

8. Problem 1: 2/8 + 3/8 = 5/8 Can it be simplified? 12/8/2009 8 Bitsy Griffin Lessons 2-24 & 25

9. Problem 1: How much more did Freddie eat? 3/8 - 2/8 = 1/8 Can it be simplified? 12/8/2009 9 Bitsy Griffin Lessons 2-24 & 25

10. Problem 2: How would we solve: ¼ + 2/3 Common denominator is? 12 12/8/2009 10 Bitsy Griffin Lessons 2-24 & 25

11. Problem 2: ¼ = ?/12 3/12 2/3 = ?/12 8/12 12/8/2009 11 Bitsy Griffin Lessons 2-24 & 25

12. Problem 2: 3/12 + 8/12 = 11/12 Can it be simplified? 12/8/2009 12 Bitsy Griffin Lessons 2-24 & 25

13. Problem 2: 3/12 + 8/12 = 11/12 Can it be simplified? 12/8/2009 13 Bitsy Griffin Lessons 2-24 & 25

14. Problem 3: Rosa bought 4/6 yd of copper pipe. She used ½ yd to repair the shower. 12/8/2009 14 Bitsy Griffin Lessons 2-24 & 25

15. Problem 3: How much pipe does she have left? Set up problem. 12/8/2009 15 Bitsy Griffin Lessons 2-24 & 25

16. Problem 3: 4/6 – ½ = What do we need to do? 12/8/2009 16 Bitsy Griffin Lessons 2-24 & 25

17. Problem 3: ½ = ?/6 3/6 4/6 – 3/6 = 1/6 Can it be simplified? 12/8/2009 17 Bitsy Griffin Lessons 2-24 & 25

18. Problem 3: ¾ - 1/3 = What is the LCD? 12 12/8/2009 18 Bitsy Griffin Lessons 2-24 & 25

19. Problem 3: ¾ = ?/12 9/12 1/3 = ?/12 4/12 12/8/2009 19 Bitsy Griffin Lessons 2-24 & 25

20. Problem 3: 9/12 - 4/12= 5/12 Can it be simplified? 12/8/2009 20 Bitsy Griffin Lessons 2-24 & 25

21. EQ: How do I add & subtract fractions when the denominator is different? 12/8/2009 21 Bitsy Griffin Lessons 2-24 & 25