4-8 Adding and Subtracting with Like Denominators Course 1 Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day

Course Adding and Subtracting with Like Denominators Warm Up Write each mixed number as an improper fraction __ __ __ 11 5 __ 23 7 __ 17 2 __ 49 5 __ __

Problem of the Day Marge has six coins that total $1.15. She cannot make change for $1.00, a half- dollar, a quarter, a dime, or a nickel. What coins does she have? half dollar, quarter, 4 dimes Course Adding and Subtracting with Like Denominators

Learn to add and subtract fractions with like denominators. Course Adding and Subtracting with Like Denominators

Additional Example 1: Application 1 4 __ = = After 2 hours inch of snow fell Add the numerators. Keep the same denominator Write your answer in simplest terms. Snow was falling at a rate of inch per hour. How much snow fell after two hours? Write your answer in simplest form. += Course Adding and Subtracting with Like Denominators

Try This: Example __ = = After 2 hours inch of rain fell. Add the numerators. Keep the same denominator. Write your answer in simplest terms. Rain was falling at a rate of inch per hour. How much rain fell after two hours? Write your answer in simplest form. += Course Adding and Subtracting with Like Denominators

Additional Example 2A: Subtracting Like Fractions and Mixed Numbers Subtract. Write the answer in simplest form. A. 1 – 5 5 __ = – To get a common denominator, rewrite 1 as a fraction with a denominator of 5. Subtract the numerators. Keep the same denominator. = ― Course Adding and Subtracting with Like Denominators

Additional Example 2B: Subtracting Like Fractions and Mixed Numbers Subtract. Write the answer in simplest form. B. 5 – __ 4 12 __ – Subtract the fractions. Then subtract the whole numbers. = __ 5 12 __ __ Write your answer in simplest form. Course Adding and Subtracting with Like Denominators

Try This: Example 2A Subtract. Write the answer in simplest form. A. 1 – 6 6 __ = – To get a common denominator, rewrite 1 as a fraction with a denominator of 6. Subtract the numerators. Keep the same denominator. = – Course Adding and Subtracting with Like Denominators

Try This: Example 2B 4 12 __ 3 12 __ – Subtract the fractions. Then subtract the whole numbers. = __ 7 12 __ __ Write your answer in simplest form. Subtract. Write the answer in simplest form. B. 4 – 2 Course Adding and Subtracting with Like Denominators

Evaluate the expression for x =. Write each answer in simplest form. 5 9 __ A. 2 9 __ – – – x x = 1 3 = Write the expression. Substitute for x and subtract the numerators. Keep the same denominator. Write your answer in simplest form. 2 9 __ Course Adding and Subtracting with Like Denominators Additional Example 3A: Evaluating Expressions with Fractions

Evaluate the expression for x =. Write each answer in simplest form. 4 9 __ B. 2 9 __ x x = 2 3 = Write the expression. Substitute for x. Add the fractions. Then add the whole numbers. Write your answer in simplest form. 2 9 __ , or 8 3 __ Course Adding and Subtracting with Like Denominators Additional Example 3B: Evaluating Expressions with Fractions

Evaluate the expression for x =. Write each answer in simplest form. 8 9 __ C. 2 9 __ x x __ = Write the expression. Substitute for x and subtract the numerators. Keep the same denominator. 2 9 __ 1, or 1 9 __ Course Adding and Subtracting with Like Denominators Additional Example 3C: Evaluating Expressions with Fractions

Try This: Example 3A Evaluate the expression for x =. Write each answer in simplest form. 4 6 __ A. 2 6 __ – – – x x = 1 3 = Write the expression. Substitute for x and subtract the numerators. Keep the same denominator. Write your answer in simplest form. 2 6 __ Course Adding and Subtracting with Like Denominators

Try This: Example 3B Evaluate the expression for x =. Write each answer in simplest form. 1 6 __ B. 2 6 __ x x = 1 2 = Write the expression. Substitute for x and subtract the numerators. Keep the same denominator. Write your answer in simplest form. 2 6 __ Course Adding and Subtracting with Like Denominators

Try This: Example 3C Evaluate the expression for x =. Write each answer in simplest form. 5 6 __ C. 2 6 __ x x = Write the expression. Substitute for x and subtract the numerators. Keep the same denominator. 2 6 __ 1, or 1 6 __ Course Adding and Subtracting with Like Denominators

Lesson Quiz Add or subtract. Write each answer in simplest form – 2. 1 – 4. Evaluate – x for x = __ 3 10 __ __ 6 21 __ ___ 3 4 __ 2 11 __ __ 6 3 miles Weston walks of a mile every day. How far will he have walked in 4 days? Course Adding and Subtracting with Like Denominators