1. 5-2 6 th grade math Adding and Subtracting with Like Denominators

2. Objectives Add and subtract fractions and mixed numbers with like denominators. Why? To know how to solve all types of number sense problems.

3. California State Standards NS 2.1: Solve problems involving addition, subtraction, … of positive fractions and explain why a particular operation was used for a given situation… NS 2.0 : Calculate and solve problems involving addition, subtraction, … MR 2.1: Use estimation to verify the reasonableness of calculated results.

4. Vocabulary Like denominators- – fractions whose denominators are the same  +  Simplify (simplest form, reduced form)- – when the GCF of the numerator and denominator is one 2 = (divide by 5) = 1 10 = (divide by 5) 5

5. How to Add Fractions with like Denominators Example 1. I+  1.Add the numerator. 2.Keep the denominators the same. 3.Simplify, if possible. Here’s how to solve: I+  = 4 = 8 1 2

6. How to Add Fractions with like Denominators, with a “Mixed/Improper” Answers. Example 2. 9 3 + 7 7 8 8 1.Add the fractions. 2.Add the whole numbers. 3.Simplify the sum. 9 3 8 7 + 8 = 10 8 =16 10 8 10/8 = 1 2/10 = 1  + 16 = = 16 

7. How to Subtract Fractions with like Denominators Example 3 7 - 3 10 1.Subtract the numerators 2.Use the common denominator. 3.Simplify, if possible. 7 - 3 10 4 = 2 10 5

8. How to Subtract Fractions with like Denominators, when needing “to borrow.” 4  -2-2 1.Rename the top fraction before you subtract, because  < . 2.Subtract the fractions and then whole numbers. 3.Simplify, if possible. 4  -2-2 3 4 4 - 2 3 - 4 2 = 1 4 2 = 1 = 1 

9. Try It! 1) 11 - 4 15 15 2)  +  3)  -  4) 7 - 3 12 12 5) 8 - 2 9 9 Answers: 1) 7 15 2)  3)  4)  5) 

10. How it works …. 2) 1/8 + 3/8 = 4/8 = ½ 3) 7/8- 5/8 = 2/8 = ¼ 4)7/12 – 3/12 = 4/12 = 1/3 5)8/9 – 2/9 = 6/9 = 2/3

11. Try some more!! 6) 4  - 2  7) 8 6 + 4 7 8 8 8) 3 6 + 1 5 7 7 9) 6 – 4  Answers: 6) 1  7) 13 5 8 8) 5 4 7 9) 1 

12. How it works! 6)4 1/3 – 2 2/3 = 3 3/ 3 – 2 2/3 1 1/3 7)8 6/8 + 4 7/8 = 13/8 = 1 5/8 8 + 4 = 12 12 + 1 5/8 = 13 5/8 8)3 6/7 + 1 5/7 11/7 = 1 4/7 3 + 1 = 4 4 + 1 4/7 = 5 4/7 9)S6 - 4 ¾ 5 4/4 - 4 ¾ = 1 ¼

13. Objective Review Add and subtract fractions and mixed numbers with like denominators. Why? You know how to solve all types of number sense problems.

14. Independent Practice 1.Complete problems 13-19. 2.Problems 20, 21 for a challenge. 3.Remember to copy the problem first. 4.Show all of your work! When finished: – If time, complete the Mixed Review problems 22-24. – If still more time, complete your Accelerated Math.