Learning Objective

1. Learning Objective Name __________________________ Today, we will subtract fractions with unlike denominators. CFU What are we going to do today? Activate (or provide) Prior Knowledge Fraction A fraction is a number that represents partof a whole. numerator Fractions with like denominators have the same number of equal parts. 3 denominator 4 Subtract fractions with like denominators. Hint: Subtract numerators and keep the denominators the same. CFU Students, you already know how to subtract fractions with like denominators. Today, we will subtract fractions with unlike denominators.

2. Concept Development Fractions with unlikedenominators have a different number of equal parts. The least common denominator(LCD) is the lowest multiple shared by a set of denominators. To subtract fractions, both fractions must have likedenominators. • To subtract fractions with unlike denominatorsuse the least common denominator (LCD) to create equivalent1 fractions. 1 equal value Subtracting Fractions with Unlike Denominators - - = = 1 5 6 1 3 10 10 10 5 2 - = Equivalent Fractions TheLCDof is10. and × × = = 2 6 3 1 1 5 3 5 5 5 10 10 5 2 2 2 CFU Which pair of fractions is ready to be subtracted? How do you know? A B In your own words, how do you subtract fractions with unlike denominators? To subtract fractions with unlike denominators __________.

3. Skill Development/Guided Practice To subtract fractions, both fractions must have likedenominators. Subtract fractions with unlike denominators. 1. 2. 2: 2, 4, 6, 8 2: 2, 4, 6, 8, 10 × × 3: 3, 6, 9, 12 5: 5, 10, 15, 20 × × 4. 3. 8: 8, 16, 24, 32 4: 4, 8, 12, 16 × 6: 6, 12, 18, 24 × 12: 12, 24, 36, 48 × × CFU (#2) How did I/you find the least common denominator? (#3) How did I/you create equivalent fractions? (#4) How did I/you subtract fractions?

4. Skill Development/Guided Practice (continued) To subtract fractions, both fractions must have likedenominators. Subtract fractions with unlike denominators. 5. Sherry bought of a pound of red apples and of a pound of green apples. How much more red apples than green apples does Sherry have? 4: 4, 8, 12, 16 × × 2: 2, 4, 6, 8 Sherry has ____ of a pound more red apples than green apples. 6. Tom bought of a pound of oranges and of a pound of bananas. How much more oranges than bananas did he buy? 3: 3, 6, 9, 12, 15 × × 5: 5, 10, 15, 20 Tom bought ____ of a pound more oranges than bananas. CFU (#2) How did I/you find the least common denominator? (#3) How did I/you create equivalent fractions? (#4) How did I/you subtract fractions?

5. Relevance To subtract fractions, both fractions must have like denominators. 1. Subtracting fractions will help solve real-life problems. of the pie was left over after the party. Erick just ate of the pie. How much pie is left? - = There is of the pie left. - = 2. Subtracting fractions will help you do well on tests. Sample Test Question 53. A B C D CFU Does anyone else have another reason why it is relevant to subtract fractions with unlike denominators? (pair-share) Why is it relevant to subtract fractions with unlike denominators? You may give me one of my reasons or one of your own. Which reason is more relevant to you? Why?

6. A B To subtract fractions, both fractions must have like denominators. Skill Closure Subtract fractions with unlike denominators. 4: 4, 8, 12, 16 1. × × 8: 8, 16, 24, 32 2. Carmen bought of a pound of grapes and of a pound of nectarines. How many more pounds of nectarines than grapes did Carmen buy? 4: 4, 8, 12, 16 × × 2: 2, 4, 6, 8 Carmen bought ____ of a pound more grapes than nectarines. Constructed Response Closure Which pair of fractions is ready to be subtracted? Explain your answer. __________________________________________________ __________________________________________________ Summary Closure What did you learn today about subtracting fractions with unlike denominators? Day 1 ______________________________________________________________ Day 2 ______________________________________________________________

7. Independent Practice Name __________________________ To subtract fractions, both fractions must have likedenominators. Subtract fractions with unlike denominators. 1. 2. 6: 6, 12, 18, 24 8: 8, 16, 24, 32 × × 3: 3, 6, 9, 12 12: 12, 24, 36, 48 × × 3. The Smith family bought a pizza. Jason ate of the pizza and Jamie ate of the pizza. How much more pizza did Jason eat than Jamie? 7: 7, 14, 21, 28, 35 × × 4: 4, 8, 12, 16, 20, 24, 28 Jason ate ____ of a pizza more than Jamie.

8. Periodic Review 1 Name __________________________ To subtract fractions, both fractions must have likedenominators. Subtract fractions with unlike denominators. 1. 2. 12: 12, 24, 36 6: 6, 12, 18, 24, 32 × × 4: 4, 8, 12, 16 12: 12, 24, 36, 48 × × 3. Geoff has of a pound of cashews and buys of a pound of pecans. How many more pounds of cashews does he have than pecans? 4: 4, 8, 12, 16 × × 6: 6, 12, 18 Geoff has ____ of a pound more cashews than pecans.

9. Periodic Review 2 Name __________________________ To subtract fractions, both fractions must have likedenominators. Subtract fractions with unlike denominators. 1. 2. 6: 6, 12, 18, 24 10: 10, 20, 30, 40 × × 8: 8, 16, 24 4: 4, 8, 12, 16, 20 × × 3. Alfredo bought some fruit. He got of a pound of apples and of a pound of pears. How many more pounds of apples than pears did Alfredo buy? 8: 8, 16, 24 × × 4: 4, 8, 12 Alfredo bought ____ of a pound more apples than pears.

10. Periodic Review 3 Name __________________________ To subtract fractions, both fractions must have likedenominators. Subtract fractions with unlike denominators. 1. 2. 12: 12, 24, 36 5: 5, 10, 15, 20 × × 4: 4, 8, 12, 16 10: 10, 20, 30 × × 3. Alice bought some beans. She got of a pound of lima beans and of a pound of pinto beans. How many more pounds of pinto beans than lima beans did she buy? 8: 8, 16, 24, 32, 40 × × 5: 5, 10, 15, 20, 25, 30, 35, 40 Alice bought ____ of a pound more pinto beans than lima beans.