ALEX Classroom Resource

  

Making Math Matter: Multiplication of a Whole Number by a Fraction

  Classroom Resource Information  

Title:

Making Math Matter: Multiplication of a Whole Number by a Fraction

URL:

https://aptv.pbslearningmedia.org/resource/e98e8ff0-38fd-46dd-a575-3523c0f43328/multiplication-of-a-whole-number-by-a-fraction/

Content Source:

PBS
Type: Audio/Video

Overview:

In this video, teachers will learn classroom strategies for teaching how to multiply a whole number by a fraction in this professional development video from Making Math Matter.

Content Standard(s):
Mathematics
MA2019 (2019)
Grade: 4
16. Apply and extend previous understandings of multiplication to multiply a whole number times a fraction.

a. Model and explain how a non-unit fraction can be represented by a whole number times the unit fraction.

Example:
9/8=9 x 1/8

b. Extend previous understanding of multiplication to multiply a whole number times any fraction less than one.

Example: 4 x 2/3= 4 x 2/3= 8/3

c. Solve word problems involving multiplying a whole number times a fraction using visual fraction models and equations to represent the problem.

Examples: 3 x 1/2, 6 x 1/8
Unpacked Content
Evidence Of Student Attainment:
Students:
  • Model and explain a fraction as a multiple of a unit fraction.

  • Example: 5/3 = 1/3 + 1/3 + 1/3 + 1/3 + 1/3 or 5 x 1/3 or (5 x 1)/3.
  • Multiply a whole number times any fraction less than 1 and justify the product.

  • Example: 5 x 2/3 is 5 sets of two-thirds, which is ten-thirds. or 5 x 2/3 = 5 x (2 x 1/3) = (5 x 2) x 1/3 = 10 x 1/3 or 10/3.
  • Solve word problems involving multiplying a whole number times a fraction using a visual model and equation to represent the problem.
Teacher Vocabulary:
  • Whole number
  • Fraction
  • Non-unit fraction
  • Unit fraction
  • Fraction less than one
  • Fraction greater than one
  • Visual fraction model
  • Equation
  • Decompose
  • Recompose
  • Compose
Knowledge:
Students know:
  • Models or equations to represent multiplication situations.
  • The fraction a/b is equivalent to the unit fraction 1/b being iterated or "copied" the number of times indicated by the numerator, a.
Skills:
Students are able to:
  • Model and explain how a non-unit fraction can be expressed as multiplication.
  • Multiply a whole number times any fraction less than one.
  • Solve word problems involving a whole number times a fraction using a visual fraction model and equation to represent the problem.
Understanding:
Students understand that:
  • Previous work involving multiplication with whole numbers can be extended to fractions in showing multiplication as putting together equal-sized fractional groups.
  • Problem solving situations involving multiplication of a whole number times a fraction can be solved using a variety of strategies, models, and representations.
Diverse Learning Needs:
Essential Skills:
Learning Objectives:
M.4.16.1: Recognize fractions in their simplest forms.
M.4.16.2: Express whole numbers as fractions, and recognize fractions that are equivalent to whole numbers.
M.4.16.3: Demonstrate an understanding of fractional parts.
M.4.16.4: Apply properties of operations as strategies to multiply and divide.
M.4.16.5: Recall basic multiplication facts.
M.4.16.6: Define multiple.
M.4.16.7: Compare two fractions with the same numerator or the same denominator by reasoning about their size.
M.4.16.8: Recognize that comparisons are valid only when the two fractions refer to the same whole.
M.4.16.9: Record results of comparisons with the symbols >, =, or <, and justify the conclusions, e.g., by using a visual fraction model.
M.4.16.10: Name the first ten multiples of each one-digit natural number.
M.4.16.11: Express whole numbers as fractions, and recognize fractions that are equivalent to whole numbers.
M.4.16.12: Solve simple fractions using multiplication strategies.
M.4.16.13: Recognize equivalent forms of fractions.
M.4.16.14: Multiply proper fractions with common denominators 2-10.
M.4.16.15: Solve word problems using whole numbers.
M.4.16.16: Write number sentences for word problems.
M.4.16.17: Identify key terms in word problems.
M.4.16.18: Multiply and divide within 100.
M.4.16.19: Recall basic multiplication facts.

Prior Knowledge Skills:
  • Define fraction, numerator, and denominator.
  • Identify the parts of a fraction a/b as the quantity formed by a parts and size 1/b.
  • Label numerator, denominator, and fraction bar.
  • Identify parts of a whole with two, three, or four equal parts.
  • Distinguish between equal and non-qual parts.
  • Partition circles and rectangles into two and four equal shares; describe the shares using the words halves, fourths, and quarters; and use the phrases half of, fourth of, and quarter of.
  • Demonstrate conceptual understanding of adding or subtracting 10 using concrete models.
  • Recognize the place value of ones, tens and hundreds.
  • Count forward and backward by 100.
  • Count forward and backward by 10.

Alabama Alternate Achievement Standards
AAS Standard:
M.AAS.4.15 Model decomposing fractions having like denominators, using visual fraction models (limit to half and fourths).


Mathematics
MA2019 (2019)
Grade: 5
12. Apply and extend previous understandings of multiplication to find the product of a fraction times a whole number or a fraction times a fraction.

a. Use a visual fraction model (area model, set model, or linear model) to show (a/b) x q and create a story context for this equation to interpret the product as a parts of a partition of q into b equal parts.

b. Use a visual fraction model (area model, set model, or linear model) to show (a/b) x (c/d) and create a story context for this equation to interpret the product.

c. Multiply fractional side lengths to find areas of rectangles, and represent fraction products as rectangular areas.

d. Find the area of a rectangle with fractional side lengths by tiling it with unit squares of the appropriate unit fraction side lengths to show that the area is the same as would be found by multiplying the side lengths.
Unpacked Content
Evidence Of Student Attainment:
Students:
Given a fraction times a whole number,
  • use visual models to illustrate the product to develop the procedure (a/b) × q.
  • Create a story context for the equation (a/b) × q.
Given a fraction times a fraction,
  • Use visual models to illustrate the product to develop the procedure (a/b) × (c/d).
  • Create a story context for the equation (a/b) × (c/d).
Given a rectangle with two fractional side lengths,
  • Use an area model to illustrate and find the rectangular area.
  • Find the area by tiling it with unit squares of the appropriate unit fraction.
Given a rectangle with fractional side lengths including mixed numbers,
  • Use an area model to illustrate and find the rectangular area to lead to answers in the form of whole numbers or mixed numbers.

  • Example: Using an area model, a rectangle with dimensions of 1 1/2 x 1 2/3 will have partial products of 1, 1/2, 1/3, and 1/6 and the sum of the partial products will give an area of 2 sq units.
  • Use an area model to find the area of a rectangle by tiling the rectangle with unit squares.

  • Example: Using an area model, a rectangle with dimensions 1 1/2 x 1 1/3 will be tiled with unit squares of 1/6 size showing the tiled partial products as 6/6, 3/6, 2/6, and 1/6 for a total area of 12/6 sq units, so it would take 12 tiles of size 1/6 units to cover the area of the rectangle.
Teacher Vocabulary:
  • Fraction
  • Fraction model
  • Whole number
  • Area
  • Area model
  • Linear model
  • Set model
  • Tiling
  • Unit squares
  • Equation
Knowledge:
Students know:
  • How to write an equation involving repeated addition with fractions as a multiplication equation of a whole number times the fraction.
    Example: 2/9 + 2/9 + 2/9 + 2/9 = 4 x 2/9 = 8/9.
  • The relationship of partial products to an area model when multiplying by two whole numbers.
  • Area of a rectangle is determined by multiplying side lengths and is found in square units.
Skills:
Students are able to:
  • Use previous understandings of multiplication to
  • Find products of a fraction times a whole number and products of a fraction times a fraction.
  • Use area models, linear models or set models to represent products.
  • Create a story context to represent equations (a/b) × q and (a/b) × (c/d) to interpret products.
  • Find area of rectangles with fractional side lengths and represent products as rectangular areas.
  • Find the area of a rectangle by tiling the area of a rectangle with unit squares.
Understanding:
Students understand that:
  • Any whole number can be written as a fraction.
  • The general rule for multiplication involving fractions can be justified through visual models.
  • A variety of contextual situations can be represented by multiplication involving fractions.
  • Tiling with unit squares can be used to find the area of a rectangle with fractional side lengths.
Diverse Learning Needs:
Essential Skills:
Learning Objectives:
M.5.12.1: Define proper fraction.
M.5.12.2: Multiply fractions using denominators between 2 and 5.
M.5.12.3: Identify proper and improper fractions.
M.5.12.4: Recall basic multiplication facts.
M.5.12.5: Model changing a whole number to a fraction.
M.5.12.6: Partition a rectangle into rows and columns of same-size squares, and count to find the total number of them.
M.5.12.7: Label the numerator and denominator of a fraction.
M.5.12.8: Count the area squares for the length and width.
M.5.12.9: Identify the width and length of a rectangle.

Prior Knowledge Skills:
  • Solve real-word problems involving multiplication of fractions and mixed numbers.
  • Write equations to represent the word situation.
  • Use visual fraction models to represent the problem.

Alabama Alternate Achievement Standards
AAS Standard:
M.AAS.5.12 Determine the product of unit fractions with unlike denominators (limited to denominators of 2, 3, 4, 10) using visual models.


Tags: fraction, multiplication, professional development, whole number
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  This resource provided by:  
Author: Stephanie Carver
Alabama State Department of Education