enVision Mathematics Topics 8-9
5th Grade; January – February (7 weeks); 2nd/3rd Trimester
enVision Mathematics Topics 8-9
5th Grade; January – February (7 weeks); 2nd/3rd Trimester
Topic Title(s):
Apply Understanding of Multiplication to Multiply Fractions (Topic 8)
Apply Understanding of Division to Divide Fractions (Topic 9)
Prepared Graduates:
MP5. Use appropriate tools strategically.
MP6. Attend to precision.
MP7. Look for and make use of structure.
Standard(s):
1. Number and Quantity
The highlighted evidence outcomes are the priority for all students, serving as the essential concepts and skills. It is recommended that the remaining evidence outcomes listed be addressed as time allows, representing the full breadth of the curriculum.
Students Can (Evidence Outcomes):
5.NF.B. Number & Operations—Fractions: Apply and extend previous understandings of multiplication and division.
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. For example, interpret 3/4 as the result of dividing 3 by 4, noting that 3/4 multiplied by 4 equals 3, and that when 3 wholes are shared equally among 4 people each person has a share of size 3/4. If 9 people want to share a 50-pound sack of rice equally by weight, how many pounds of rice should each person get? Between what two whole numbers does your answer lie? (CCSS: 5.NF.B.3)
Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction. (CCSS: 5.NF.B.4)
Interpret the product a/b × q as a parts of a partition of q into b equal parts; equivalently, as the result of a sequence of operations a × q ÷ b. For example, use a visual fraction model to show 2/3 × 4 = 8/3, and create a story context for this equation. Do the same with 2/3 × 4/5 = 8/15. (In general, a/b × c/d = ac/bd.) (CCSS: 5.NF.B.4.a)
Find the area of a rectangle with fractional side lengths by tiling it with unit squares of the appropriate unit fraction side lengths, and show that the area is the same as would be found by multiplying the side lengths. Multiply fractional side lengths to find areas of rectangles, and represent fraction products as rectangular areas. (CCSS: 5.NF.B.4.b)
Interpret multiplication as scaling (resizing), by: (CCSS: 5.NF.B.5)
Comparing the size of a product to the size of one factor on the basis of the size of the other factor, without performing the indicated multiplication. (CCSS: 5.NF.B.5.a)
Explaining why multiplying a given number by a fraction greater than 1 results in a product greater than the given number (recognizing multiplication by whole numbers greater than 1 as a familiar case); explaining why multiplying a given number by a fraction less than 1 results in a product smaller than the given number; and relating the principle of fraction equivalence a/b = (n × a)/(n × b) to the effect of multiplying a/b by 1. (CCSS: 5.NF.B.5.b)
Solve real-world problems involving multiplication of fractions and mixed numbers, e.g., by using visual fraction models or equations to represent the problem. (CCSS: 5.NF.B.6)
Apply and extend previous understandings of division to divide unit fractions by whole numbers and whole numbers by unit fractions. (Students able to multiply fractions in general can develop strategies to divide fractions in general, by reasoning about the relationship between multiplication and division. But division of a fraction by a fraction is not a requirement at this grade.) (CCSS: 5.NF.B.7)
Interpret division of a unit fraction by a non-zero whole number, and compute such quotients. For example, create a story context for 1/3 ÷ 4, and use a visual fraction model to show the quotient. Use the relationship between multiplication and division to explain that 1/3 ÷ 4 = 1/12 because 1/12 × 4 = 1/3. (CCSS: 5.NF.B.7.a)
Interpret division of a whole number by a unit fraction, and compute such quotients. For example, create a story context for 4 ÷ 1/5, and use a visual fraction model to show the quotient. Use the relationship between multiplication and division to explain that 4 ÷ 1/5 = 20 because 20 × 1/5 = 4. (CCSS: 5.NF.B.7.b)
Solve real-world problems involving division of unit fractions by nonzero whole numbers and division of whole numbers by unit fractions, e.g., by using visual fraction models and equations to represent the problem. For example, how much chocolate will each person get if 3 people share 1/2 lb of chocolate equally? How many 1/3-cup servings are in 2 cups of raisins? (CCSS: 5.NF.B.7.c)
Solve problems requiring calculations that scale whole numbers and fractions. (Entrepreneurial Skills: Critical Thinking/Problem Solving)
Use fraction models and arrays to interpret and explain fraction calculations. (MP5)
Attend carefully to the underlying unit quantities when solving problems involving multiplication and division of fractions. (MP6)
Contrast previous understandings of multiplication modeled as equal groups to multiplication as scaling, which is necessary to understand multiplying a fraction or whole number by a fraction, and how the operation of multiplication does not always result in a product larger than both factors. (MP7)
Inquiry Questions
How can you rewrite the fraction 5/3 with an addition equation? How can you rewrite it with a multiplication equation? How does it make sense that both equations are accurate?
If we can describe the product of 5 × 3 as “three times as big as 5,” what does that tell us about the product of 5 × 1/2? What about 1/5 × 1/2?
Coherence Connections
This expectation represents major work of the grade.
In previous grades, students base understanding of multiplication on its connection to addition, groups of equivalent objects, and area models. In Grade 4, students add and subtract fractions and mixed numbers with like denominators, recognize and generate equivalent fractions, and compare fractions with different numerators and denominators.
This expectation connects with several others in Grade 5: (a) performing operations with multi-digit whole numbers and with decimals to hundredths, (b) writing and interpreting numerical expressions, and (c) representing and interpreting data.
In Grade 6, students (a) understand ratio concepts and use ratio reasoning to solve problems, (b) apply and extend previous understandings of multiplication and division to divide fractions by fractions, (c) reason about and solve one-variable equations and inequalities, and (d) solve real-world and mathematical problems involving area, surface area, and volume.
Academic Vocabulary & Language Expectations:
Assessments:
Instructional Resources & Notes:
enVision Mathematics Topics 8-9
Additional enVision Mathematics Resources
Let's Investigate! Photo Enlargement (TE) (supports Lessons 8-7, 8-8)
Let's Investigate! For the Dogs (TE) (supports Lessons 9-5, 9-6)
3-Act Math Recording Sheets (Topic 9)
Additional Math Games: Fraction Multiplication & Division (additional materials and preparation may be required)
Tier 1 Intervention & Supports (i-Ready Tools for Instruction):
Tier 1 Intervention Topic 8: Multiply a Whole Number and a Fraction, Understand Fraction Multiplication, Multiply Fractions, Multiplying Fractions to Solve Word Problems
Tier 1 Intervention Topic 9: Interpreting Fractions as Division, Dividing with Unit Fractions, Dividing Unit Fractions to Solve Word Problems
Coherence Map/Concept Progressions: 5.NF.B.3, 5.NF.B.4.a, 5.NF.B.6, 5.NF.B.7.c
Advanced Differentiation:
Advanced students should also demonstrate mastery with the content in the following lessons to provide access to advanced mathematics courses in middle school:
enVision Mathematics Topic 17: Step Up to Grade 6
Lesson 17-1: Understand Division of Fractions