1. 5-2 Adding and Subtracting with Unlike Denominators Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day Lesson Quizzes Lesson Quizzes

2. 5-2 Adding and Subtracting with Unlike Denominators Warm Up Add. Write each answer in simplest form. 1. +2. + 3. + 4. + 1 7 __ 1 7 8 15 __ 3 15 __ 7 9 2 9 11 20 __ 4 20 __ 2 7 11 15 __ 1 3 4

3. 5-2 Adding and Subtracting with Unlike Denominators Problem of the Day If it takes 12 minutes to cut a pipe into three pieces, how long would it take to cut the pipe into four pieces? 18 minutes

4. 5-2 Adding and Subtracting with Unlike Denominators Learn to add and subtract fractions with unlike denominators.

5. 5-2 Adding and Subtracting with Unlike Denominators Vocabulary least common denominator (LCD) ‏

6. 5-2 Adding and Subtracting with Unlike Denominators The Pacific Ocean covers of Earth’s surface. The Atlantic Ocean covers of Earth’s surface. To find the fraction of Earth’s surface that is covered by both oceans, you can add and, which are unlike fractions. 1 3 __ 1 3 1 5 1 5

7. 5-2 Adding and Subtracting with Unlike Denominators Fractions that represent the same value are equivalent. Remember! To add or subtract unlike fractions, first rewrite them as equivalent fractions with a common denominator.

8. 5-2 Adding and Subtracting with Unlike Denominators Additional Example 1: Cooking Application Mark made a pizza with pepperoni covering of the pizza and onions covering another. What fraction of the pizza is covered by pepperoni and onions? 1 4 __ 1 3 1 4 1 3 _____ + Find a common denominator for 4 and 3: 4 x 3 = 12. ? 1 4 __ 1 3 1 4 1 3 Add +.

9. 5-2 Adding and Subtracting with Unlike Denominators Additional Example 1 Continued Write equivalent fractions with 12 as the common denominator. 1 4 __ 1 3 _______ + 3 12 __ 4 12 __ _____ Add the numerators. Keep the common denominator. 1 4 __ 1 3 7 12 __ 1 12 1 12 1 12 1 12 1 12 1 12 1 12 The pepperoni and onions cover of the pizza. 7 12 __

10. 5-2 Adding and Subtracting with Unlike Denominators Check It Out: Example 1 Tori made a pizza with peppers covering of the pizza and ham covering another. What fraction of the pizza is covered by ham and peppers? 1 3 __ 1 2 1 3 1 2 ? 1 3 1 2 _____ + Find a common denominator for 3 and 2: 3 X 2 = 6. 1 3 __ 1 2 Add +.

11. 5-2 Adding and Subtracting with Unlike Denominators Check It Out: Example 1 Continued Write equivalent fractions with 6 as the common denominator. 1 3 __ 1 2 _______ + 2 6 __ 3 6 _____ Add the numerators. Keep the common denominator. 5 6 __ 1 3 1 2 1616 1616 1616 1616 1616 The peppers and ham cover of the pizza. 5 6 __

12. 5-2 Adding and Subtracting with Unlike Denominators You can use any common denominator or the least common denominator to add and subtract unlike fractions. The least common denominator (LCD) is the least common multiple of the denominators.

13. 5-2 Adding and Subtracting with Unlike Denominators Additional Example 2A: Adding and Subtracting Unlike Fractions Add or subtract. Write each answer in simplest form. Method 1: Multiplying denominators. 7 10 __ 3 8 – 7 10 __ 3 8 – 56 80 __ 30 80 __ Multiply the denominators. 10 8 = 80 Write equivalent fractions with a common denominator. Subtract. Write the answer in simplest form. 26 80 __ 13 40 __ –

14. 5-2 Adding and Subtracting with Unlike Denominators Additional Example 2B: Adding and Subtracting Unlike Fractions Add or subtract. Write each answer in simplest form. Method 2: Use the LCD. – 11 12 __ 3 8 – 11 12 __ 3 8 – 22 24 __ 9 24 __ Multiples of 8: 8, 16, 24, … The LCD is 24. Write equivalent fractions with a common denominator. Subtract. 13 24 __ Multiples of 12: 12, 24, …

15. 5-2 Adding and Subtracting with Unlike Denominators Additional Example 2C: Adding and Subtracting Unlike Fractions Add or subtract. Write each answer in simplest form. Method 3: Use mental math. 5 16 __ 1 8 + 5 16 __ 1 8 + 5 16 __ 2 16 __ Think: 16 is a multiple of 8, so the LCD is 16. Rewrite with a denominator of 16. Add. 7 16 __ 1 8 +

16. 5-2 Adding and Subtracting with Unlike Denominators Additional Example 2D: Adding and Subtracting Unlike Fractions Add or subtract. Write each answer in simplest form. Method 3: Use mental math. 5 16 __ 1 8 – 5 16 __ 1 8 – 5 16 __ 2 16 __ Think: 16 is a multiple of 8, so the LCD is 16. Rewrite with a denominator of 16. Subtract. 3 16 __ 1 8 –

17. 5-2 Adding and Subtracting with Unlike Denominators Check It Out: Example 2A Add or subtract. Write each answer in simplest form. Method 1: Multiplying denominators. – 8 10 __ 2 6 – 8 10 __ 2 6 – 48 60 __ 20 60 __ Multiply the denominators. 10 6 = 60 Write equivalent fractions with a common denominator. Subtract. Write the answer in simplest form. 28 60 __ 7 15 __

18. 5-2 Adding and Subtracting with Unlike Denominators Check It Out: Example 2B Add or subtract. Write each answer in simplest form. Method 2: Use the LCD. – 4 7 __ 1 3 – 4 7 1 3 – 12 21 __ 7 21 __ Multiples of 3: 3, 6, 9, 12, 15, 18, 21, … The LCD is 21. Write equivalent fractions. Subtract. 5 21 __ Multiples of 7: 7, 14, 21, …

19. 5-2 Adding and Subtracting with Unlike Denominators Check It Out: Example 2C Add or subtract. Write each answer in simplest form. Method 3: Use mental math. 3 12 __ 1 6 + 3 12 __ 1 6 + 3 12 __ 2 12 __ Think: 12 is a multiple of 6, so the LCD is 12. Rewrite with a denominator of 12. Add. 5 12 __ 1 6 +

20. 5-2 Adding and Subtracting with Unlike Denominators Check It Out: Example 2D Add or subtract. Write each answer in simplest form. Method 3: Use mental math. 3 12 __ 1 6 – 3 12 __ 1 6 – 3 12 __ 2 12 __ Think: 12 is a multiple of 6, so the LCD is 12. Rewrite with a denominator of 12. Subtract. 1 12 __ 1 6 –

21. 5-2 Adding and Subtracting with Unlike Denominators Standard Lesson Quiz Lesson Quizzes Lesson Quiz for Student Response Systems

22. 5-2 Adding and Subtracting with Unlike Denominators Lesson Quiz Add or subtract. Write each answer in simplest form. 1. +2. – 3. – 4. + 5. Bonnie is making oatmeal bars and the recipes calls for cup of brown sugar. If she has cup of brown sugar, how much more does she need? 3 8 __ 1 6 1 2 1 8 5 12 __ 1 6 1 6 1 8 3 4 1 3 13 24 __ 3 8 1 4 7 24 __ 5 12 __ cup

23. 5-2 Adding and Subtracting with Unlike Denominators 1. Add and identify the answer in simplest form. A. C. B. D. Lesson Quiz for Student Response Systems

24. 5-2 Adding and Subtracting with Unlike Denominators 2. Subtract and identify the answer in simplest form. A. C. B. D. Lesson Quiz for Student Response Systems

25. 5-2 Adding and Subtracting with Unlike Denominators 3. Subtract and identify the answer in simplest form. A. C. B. D. Lesson Quiz for Student Response Systems

26. 5-2 Adding and Subtracting with Unlike Denominators 4. Add and identify the answer in simplest form. A. C. B. D. Lesson Quiz for Student Response Systems

27. 5-2 Adding and Subtracting with Unlike Denominators 5. Donna is making tomato soup and the recipe calls for kg of tomato. If she has kg of tomatoes, how much more does she need? A. C. B. D. Lesson Quiz for Student Response Systems