1.) 4 – 2 3/8 = 2.) 5 1/9 – 2 8/9 = 3 8 4 4 1 9 + 9 = 10 9 9 5 - 2 3 8 - 2 8 9 1 5 8 2 2 9

3-4 Multiplying Fractions 3-5 Dividing Fractions

Multiplying Fractions Big Rocks Simplify if needed Multiply numerators Multiply denominators

Multiply. Write the answer in simplest form. 3 Write –12 as a fraction. A. –12 · 4 3 Simplify. 3 12 3 –12 · = – · Multiply numerators. Multiply denominators. 4 1 4 1 9 = – = – 9 1 You can write any integer as a fraction with a denominator of 1. Remember!

Additional Example 2B: Multiplying Fractions Multiply. Write the answer in simplest form. . 1 3 Simplify. B. · 3 8 Multiply numerators. Multiply denominators. 1 3 8 · 1 1 = 8 1

. Try This: Example 2B Multiply. Write the answer in simplest form. 1 Simplify. 6 B. · 1 6 9 1 6 9 · 1 = Multiply numerators. Multiply denominators. 9 1

Additional Example 3A: Multiplying Mixed Numbers Multiply. Write the answer in simplest form. 2 2 · 1 Write the mixed number as an improper fraction. A. 5 3 1 Simplify. 2 5 = · 5 3 Multiply numerators. Multiply denominators. 1 2 = 3

Additional Example 3C: Multiplying Mixed Numbers Multiply. Write the answer in simplest form. 2 2 C. Write the mixed number as an improper fraction. 6 · 4 3 5 4 Simplify. 20 22 = · 3 5 1 Multiply numerators. Multiply denominators. 3 = 88 or 29 1

Multiply. Write the answer in simplest form. Try This: Example 3B Multiply. Write the answer in simplest form. 3 1 B. 3 7 · 1 2 6 3 21 4 = · 6 3 3 1 = 14 3 Or 4 2

How Do We Divide Fractions?

A contractor wants to build a subdivision on a Dividing Fractions A contractor wants to build a subdivision on a 2 acre tract of land that he owns. The two acres of land are to be divided into ¼ acre lots. How many lots will there be? ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ So, 2 ÷ ¼ = 8

Big Rocks – Divide Fractions 1. Rewrite first fraction 2 Big Rocks – Divide Fractions 1. Rewrite first fraction 2. Change divide to multiply 3. Flip second fraction 4. Follow multiplication rules

To find the reciprocal of a fractions, flip it! A number times it’s reciprocal equals one You need the reciprocal when dividing fractions! EXAMPLES: 2 3 5 2 2 5 2 ½ = 3 2

5 10 9 12 1 4 2 5 12 4 3 9 10 6 X 2 3 Examples of dividing fractions 5 10 9 12 KEEP SWITCH FLIP 1 4 2 3 5 9 12 10 4 6 X 2 3

3 ½ 2 ¼ 7 9 2 4 2 7 2 4 9 14 9 1 X 1 Examples of dividing fractions 3 ½ 2 ¼ Examples of dividing fractions 7 9 2 4 KEEP SWITCH FLIP 2 7 2 4 9 14 9 1 5 9 X 1

Example 1 6 2 2 ÷ 2 5 7 32 16 ÷ 5 7 2 2 32 7 14 4 = = x 16 1 5 5 5

Example 2 1 6 1 ÷ 2 9 3 10 20 ÷ 9 3 10 1 1 3 1 x = 2 3 9 20 6

Example 3 8 5 1 ÷ 13 105 5 ÷ 13 1 1 1 8 21 105 = 21 x = 13 13 13 5 1

Your Turn!!! 4 5 2 1 3 5 4 5 1 2 1 x = ÷ = 5 6 5 2 1 12 5 6 2 5 2 x = ÷ = 1 8 3 1 3 8 1 8 1 3 x = ÷ =

Homework Pg 144 #10-32 even simplify & show work & no improper fractions allowed

Quiz: Dividing Fractions 6 divided by 3 ½ = 4/5 divided by 2/5 = 1 ½ divided by 3 ¾ = 3 ½ divided by 1 ¾ = 2 ½ divided by 2 ½ = 5 1/3 divided by 4/9 = Check your answers

Answers: Dividing Fractions 6 divided by 3 ½ = 1 5/7 4/5 divided by 2/5 = 2 1 ½ divided by 3 ¾ = 2/5 3 ½ divided by 1 ¾ = 2 2 ½ divided by 2 ½ = 1 5 1/3 divided by 4/9 = 12 Back to Quiz

Pg 138 #8-30 evens Show your work Of means to multiply Homework Pg 138 #8-30 evens Show your work Of means to multiply

Lesson Quiz: Part 1 Multiply. Write each answer in simplest terms. 1 5 5 48 1. · 8 6 5 1 2 35 12 or 11 2 2. 5 · 6 1 2 17 2 1 or 8 3. 5 · 1 10 3 3 2 7 8 4. · 4 16 3