UNIT 3 - USING MODELS TO MULTIPLY & DIVIDE FRACTIONS
multiplying fractions
Standards
Apply and extend previous understandings of multiplication and division to multiply and divide fractions.
5.NF.4. Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.
5.NF.5: Interpret multiplication as scaling (re-sizing)
5.NF.6: Solve real world problems involving multiplication of fractions and mixed numbers, e.g., by using visual fraction models or equations to represent the problem.
Apply and extend previous understandings of multiplication and division to multiply and divide fractions.
5.NF.4. Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.
5.NF.5: Interpret multiplication as scaling (re-sizing)
5.NF.6: Solve real world problems involving multiplication of fractions and mixed numbers, e.g., by using visual fraction models or equations to represent the problem.
Videos
WCPSS Video Support (from YouTube Channel): Video Resources: From the Wake County Academics YouTube Channel
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Click to set custom HTML
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Strategies for Multiplying Fractions
Multiply a fraction by a whole number:
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Unit Fractions X Whole Number
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Remember that multiplication is repeated addition.
To model 1/8 x 3, you need to show 3 groups of 1/8. My product is 3/8.
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Multiply a fraction by a fraction:
When we multiply fractions, we are taking a fraction of another fraction. We can use fraction bars, number lines, and the standard algorithm to find the product of two fractions.
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dividing fractions
Standards
Apply and extend previous understandings of multiplication and division to multiply and divide fractions.
5.NF.3: Interpret a fraction as division of the numerator by the denominator (a/b = a ÷ b). Solve word problems involving division of whole numbers leading to answers in the form of fractions or mixed numbers, e.g., by using visual fraction models or equations to represent the problem.
5.NF.7: Apply and extend previous understandings of division to divide unit fractions by whole numbers and whole numbers by unit fractions.
Apply and extend previous understandings of multiplication and division to multiply and divide fractions.
5.NF.3: Interpret a fraction as division of the numerator by the denominator (a/b = a ÷ b). Solve word problems involving division of whole numbers leading to answers in the form of fractions or mixed numbers, e.g., by using visual fraction models or equations to represent the problem.
5.NF.7: Apply and extend previous understandings of division to divide unit fractions by whole numbers and whole numbers by unit fractions.
Vocabulary
unit fraction - a fraction with a numerator of 1 |
Videos
WCPSS Video Support (from YouTube Channel) |
strategies for dividing fractions
Fractions as Division
Students use models and equations to begin to develop an understanding of a fraction as the division of the numerator by the denominator.
Whole Number Divided by Unit Fraction
Angelo has 4 lbs of peanuts. He wants to give each of his friends 1/5 lb. How many friends can receive
1/5 lb of peanuts? A diagram for 4 ÷ 1/5 is shown below. Students explain that since there are five fifths in one whole, there must be 20 fifths in 4 lbs. Therefore, Angelo can give 1/5 of a pound of peanuts to 20 friends. Scenario and image from NC DPI Unpacking Document |
Unit Fraction Divided by Whole Number
Four students sitting at a table were given 1/3 of a pan of brownies to share. How much of a pan will each student get if they share the pan of
brownies equally? The diagram shows the 1/3 pan divided into 4 equal shares (1/3 ÷ 4) with each share equaling 1/12 of the pan. Therefore, each of the 4 students will get 1/12 of the pan of brownies. Scenario and image from NC DPI Unpacking Document |