Welcome to IRSC’s LIVE Virtual Lesson on: Multiplying and Dividing Fractions Instructor: Lara DiMartino

How to participate in this session:

Raising your hand

What you will learn today: Review of “What is a Fraction?”. How to multiply and divide fractions. How to change an improper fraction to a mixed number or whole number. Review of how to reduce fractions.

Why learn these skills? Fractions were invented long before decimal numbers as a way of showing portions less than 1. They're used in baking, in building, in sewing, in the stock market - they're everywhere! So, we need to understand them.

Parts of a Fraction Numerator ______________ Vinculum Denominator Also written this way: Numerator/Denominator

Understanding the Parts Numerator: The top number. It is the number of parts you have. It functions as the dividend when dividing. Denominator: The bottom number. It is the total number of parts of the whole. It functions as the divisor of the numerator when dividing.

Understanding Fractions The whole numbers are the multiples of 1. (1, 2, 3, 4, 5, and so on…)  The fractions are its parts:  its halves, thirds, fourths, fifths, and so on. ( 1/2, 1/3 , 1/4, 1/5, …)

1 written in fraction form This is 1 whole pizza. There are 8 individual slices (parts). These parts goes in the numerator spot. There are 8 slices that make up the (whole) pizza. This whole goes in the denominator spot. For this example, 1 is equal to 8/8.

A fraction is a part of 1. A fraction has a value that is less than 1. Example: This pizza shows 3 parts (numerator) left of the whole 4 pieces (denominator).

whose numerator is larger than its denominator. Let’s compare terms… Fraction A part of 1. Example: 1/8 Mixed Number A whole number with a fraction. Example: 2 ¼ Improper Fraction A fraction whose numerator is larger than its denominator. Example: 12/8 Whole Number Multiples of 1. Example: 1, 2, 3, 4, and so on…

Multiplying Fractions Step: 1 Cross reduce if possible. Step 2: Multiply the numerators and denominators. *Optional: You can choose to reduce first or last.

Example 1: Multiplying Fractions Step 1: Cross reduce if possible. 3 X 4 which becomes 1/2 x 1/2 = 8 6 Step 2: Multiply the numerators and denominators. ½ x ½ = ¼ * Make sure your answer is in simplest terms.

Example 2: Multiplying Fractions Step 1: Cross reduce if possible. 5 X 10 = which becomes 5/3 X 2/12 15 12 Step 2: Multiply the numerators and denominators. 5/3 X 2/12 = 10/ 36 WAIT! Is our answer in simplest terms? Nope! Reduce 10/36 ->

Example 3: Multiplying Fractions 7/10 X 3/14= Step 1: Cross reduce if possible. 7 X 3 => 1 X 3 10 14 10 2 Step 2: Multiply the numerators and denominators. 1/10 X 3/2 =

Dividing Fractions Step: 1 Flip the 2nd fraction. Step 2: Change the sign from division to multiplication. Step 3: Follow the steps to multiply. Step 4: If the answer is improper, change it to a mixed number or whole number. * Make sure your answer is in simplest terms.

Example 1: Dividing Fractions 1/8 2/9 = Step: 1 Flip the 2nd fraction. 1 9 = 8 2 Step 2: Change the sign from division to multiplication. 8 2 Step 3: Follow the steps to multiply. 9/16 Step 4: If the answer is improper, change it to a mixed number or whole number.

Example 2: Dividing Fractions 6/11 3/4 = Step: 1 Flip the 2nd fraction. 6 4 = 11 3 Step 2: Change the sign from division to multiplication. 6 4 = 11 3 Step 3: Follow the steps to multiply. 6/11 X 4/3 = ? Step 4: If the answer is improper, change it to a mixed number or whole number.

Example 3: Dividing Fractions 3/4 2/5 = Step: 1 Flip the 2nd fraction. 3/4 5/2 = Step 2: Change the sign from division to multiplication. 3/4 X 5/2 = Step 3: Follow the steps to multiply. Step 4: If the answer is improper, change it to a mixed number or whole number.

Changing an Improper Fraction… 15/8 Divide 8 into 15. You get 1 with a remainder of 7. 1 becomes your whole number 1 7 becomes your numerator 1 7/? Keep the original denominator of 8 1 7/8 Answer: 1 7/8

Let’s try another one… Answer: 22/5 Divide ____ into ____. You get ____ with a remainder of ____. ___ becomes your whole number ___ becomes your numerator Keep the original denominator of 5. Answer:

Practice Makes Perfect… 16/8 Divide 8 into 16. You get 2… since 8 divides evenly into 16. 2 becomes your whole number. Answer: 2

Instructional Video More on multiplying and dividing fractions…

Reminder: Is Your Answer in Simplest Terms? If not, you need to simplify (reduce). Example: 5/12 + 1/12 6/12 This can be reduced!

Reducing continued- Ask yourself…What number can divide evenly into both 6 and 12? Determine the (GCF)greatest common factor. Factors of 6: {1, 2, 3, 6} Factors of 12: { 1, 2, 3, 4, 6, 12} 6 can divide into both! 6 6 = 1 12 6 = 2 ½ is the answer in simplest terms!

Type your questions in the chat window please for whiteboard practice. Any Questions? Type your questions in the chat window please for whiteboard practice.

Print your participant window. Why? To email to your instructor as proof of attendance. To get 1 hour of credit towards your 10 hours this week. How? Place your cursor and left click your mouse on the participant window. On your keyboard, hold down the SHIFT and PRINT SCREEN keys. Then open a Word document and paste (Ctrl + V). Last, attach your word document to an email and send it to your instructor.

Final Comments This session has been recorded for you to play back and view at any time. If you have any questions regarding this topic at a later time, don’t hesitate to contact your instructor. Don’t forget to use the Smarthinking tutor feature within your class site. A tutor is available to you 24 hours a day.

Thank you for coming! I hope you will take advantage of our future LIVE virtual lessons and will attend some of those sessions as well. Have a great day!