Multiplying and Dividing Fractions Our Lesson Multiplying and Dividing Fractions

Warm up 4/5 +7/8 67/40 2/7 + 6/7 8/7 9/12 + 4/9 43/36 9/10- 6/10 3/10 4/5 +7/8 67/40 2/7 + 6/7 8/7 9/12 + 4/9 43/36 9/10- 6/10 3/10 5/8- 3/6 1/8 Confidential

Lets review what we have learned in the last lesson Addition of Fractions Addition means combining objects in two or more sets the objects must be of the same type, i.e. we combine bundles with bundles and sticks with sticks. in fractions, we can only combine pieces of the same size. In other words, the denominators must be the same. Confidential

Addition of Fractions Example 1 3 8 8 + With equal denominators The answer is (1+3) 8 Which can be simplified to 1 2 Confidential

Addition of Fractions with different denominators When the denominators are co-prime, we need to multiply the two denominators to get the common denominator When the two denominators have a common factor we find the least common denominator by factoring When one denominator is a multiple of the other denominator the multiple is the denominator Confidential

Subtraction of Fractions subtraction means taking objects away the objects must be of the same type, i.e. we can only take away apples from a group of apples - in fractions, we can only take away pieces of the same size. In other words, the denominators must be the same Confidential

Subtraction of Fractions 11 3 12 12 Example: - 11 3 11 - 3 12 12 12 - = 8 12 = Confidential

Multiplying fractions Lets get Started Multiplying fractions To multiply two fractions multiply the numerators and multiply the denominators a c b d ac bd b,d = 0 x = Confidential

Multiplication of mixed fractions First convert the mixed fraction in to an improper fraction Then multiply, numerator x numerator and denominator x denominator Then again convert answer in to mixed number 19 1 12 1 6 2 4 38 6 4 = x 31 x 38 6 x 4 = 589 12 = = 49 5 x 9 3 Improper fraction Confidential

Lets see some more Examples 2/9 x 5/7 2 x 5 10 9 x 7 63 = = 3 5 4 9 18 67 5 9 2) 3 x = x 7 36 45 18 x 67 1206 5 x 9 45 = = 26 = Confidential

To divide fractions , multiply by its multiplicative inverse Division of Fractions To divide fractions , multiply by its multiplicative inverse a c b d a d b c ÷ = x Where b, c and d = 0 Confidential

Steps for dividing fractions 1) Flip the second fraction over so that it would look like this Numerator (N) Denominator Denominator (D) Numerator 2) Now multiply the numerators and the denominators and put the product of the numerators over the product of the denominators Numerator Denominator Denominator Numerator x 2nd fraction 1st fraction changed Confidential

The number 0 has no reciprocals Check this out If the product of two numbers is 1 , they are the reciprocals of each other The number 0 has no reciprocals Confidential

Lets see some examples 1) 5/8 ÷ 7/6 5 6 30 8 7 56 = x = 4 3 4 8 36 1) 5/8 ÷ 7/6 5 6 30 8 7 56 = x = 4 3 4 8 36 5 8 5 3 15 = ÷ x = Confidential

Division of mixed fractions First convert the mixed fraction in to an improper fraction Then multiply, Numerator x Denominator Denominator x Numerator Example: 3 4 4 9 11 49 11 9 99 3 9 3 45 135 ÷ 5 x = x 2 = = Confidential

Your turn 3/7 x 3/9 9 /63 4/9 x 3/5 12/45 2/5 x 6/7 12/35 Confidential

Your turn 6) 10 1/3 ÷ 5 2/7 217/111 7) 8/11 ÷ 6/13 52/33 8) 4/7 ÷ 1/3 12/7 3 5/7 ÷ 4 3/8 455/28 21/9 ÷ ___ = 1 7/3 For Q.10 Do not use the reciprocals of the same fraction Confidential

Break Time Confidential

Click here to play a game It's GAME TIME !!!! Click here to play a game Confidential

1) In 1513, Juan Ponce de Leon discovered Florida 1) In 1513, Juan Ponce de Leon discovered Florida. His route from Puerto Rico to Florida measures about 2 ¼ inches on the map. If 1 inch represents 667miles, find the approximate length of the route. 1,500 ¾ miles Confidential

Yes, there is enough turkey for 15 people 2) Nick is serving a 12 pound turkey at a dinner party. As a rule, you should allow about ¾ of a pound of meat per person. If he invited 15 people, will he have enough turkey? Use the equation ¾ p = 12 where p is the number of people. Yes, there is enough turkey for 15 people Confidential

3) By law, the length of an official U. S 3) By law, the length of an official U.S. flag must be 1 9/10 times its width. If the width of a flag is 3 ½ feet, what is its length? 6 13/20 ft Confidential

Multiplying fractions Lets review what we learned in this lesson Multiplying fractions To multiply two fractions multiply the numerators and then multiply the denominators a c b d ac bd b,d = 0 x = Confidential

To divide fractions , multiply by its multiplicative inverse Division of Fractions To divide fractions , multiply by its multiplicative inverse a c b d a d b c ÷ = x Where b, c and d = 0 Confidential

You had a Great lesson today! Be sure to practice what you have learned today Confidential