4th Grade Mathematics Unit #3: Developing Fraction and Decimal Sense Pacing: 34 Days Unit Overview This unit is designed to build a true “fraction sense,” in much the same way we build number sense in the younger grades. All too often, students struggle with fractions because they try to treat them like whole numbers and have simply memorized algorithms or rules that are devoid of conceptual understanding. Students need multiple opportunities to explore and make sense of fractional values before they can begin working with them. Therefore a variety of physical and visual models must be incorporated throughout instruction, and the emphasis that fractions are, indeed, numbers must continually be reinforced through the use of a number line. According to Van de Walle: “In fact, what appears to be critical to learning is that the use of physical tools leads to the use of mental models, and this builds students’ understanding of fractions. Properly used, tools can help students clarify ideas that are often confused in a purely symbolic form.” In this unit students will compose and decompose fractions as well as determine and create equivalent relationships. Students will use visual models to represent fractional values and will have an opportunity to reflect on which type of models are best used to represent a fraction based on its real world context – in this unit, students will work extensively with area models, set models, and length models. Students will begin to notice connections between the models and fractions in the way both the parts and wholes are counted and begin to generate a rule for writing equivalent fractions. Students will explore and analyze various strategies to compare fractions using benchmarks, common denominators/common numerators, and reasoning about the size of parts when two fractions appear close in value based on their nearest benchmark. Students will compare fractional values with different denominators using a variety of strategies. After they’ve had an opportunity to compare fractions by reasoning about their values, students will then make connections to the previous units focus on factors and multiples to help them create common denominators for efficient comparisons. At the end of this unit, students will work with decimals for the first time and extend their understanding of equivalence to describe the equivalent relationship between fractions with denominators of 10 or 100 with decimals that represent the same value. Again, it is important for students to understand that equivalent fractions and decimals represent the same point on a number line. Place value and computation with decimals become a significant focus in grade 5, so it is important for students to have ample opportunities in grade 4 to explore the relationship between fractions and decimals. *Note: content in this unit is limited to fractions. Students will work with mixed numbers in unit 4 when they learn how to add fractions with common denominators so that they can then compose and decompose mixed fractions greater than 1 Prerequisite Skills Vocabulary 1) Identify and give multiple representations for the fractional parts of a whole (area model) 2) Recognize and represent that the denominator determines the number of equally sized pieces that make up a whole. 3) Recognize and represent that the numerator determines how many pieces of the whole are being referred to in the fraction. 4) Compare fractions with common denominators of 2, 3, 4, 6, 10, or 12 using concrete and pictorial models. 5) Compare multi-digit numbers using number lines and place value charts 6) Attend to precision when plotting whole numbers and fractions on a number line Fraction Value Numerator Denominator Area Model Set Model Part Whole Equivalent Unit Fraction Benchmark Inverse Simplify Divisible Prime Factors GCF Proper Fraction Improper Fraction Generate Mathematical Practices Convert Compose Decompose Decimal Hundredths Tenths Decimal Point Decimal Notation Expanded Size Form Common Core State Standards Additional Standards (10%) Major Standards (70%) 2 | P a g e Progression of Major Skills 4:OA.5: Patterns 4.NF.1: Identify and Generate Equivalent Fractions MP.1: Make sense of problems and persevere in solving them MP.2: Reason abstractly and quantitatively MP.3: Construct viable arguments and critique the reasoning of others MP.4: Model with mathematics MP.5: Use appropriate tools strategically MP.6: Attend to precision MP.7: Look for and make use of structure MP.8: Look for and express regularity in repeated reasoning Supporting Standards (20%) 4.NF.2: Compare Fractions with Different Denominators 4.NF.3: Compose, Decompose, Add and Subtract Fractions and Mixed Numbers 3rd Grade 4th Grade 5th Grade 1 part when a whole is partitioned into b equal parts; understand a fraction a/b as the quantity formed by a parts of size 1/b. by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions. (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. According4.NF.1: to theExplain PARCC Model Content 3.NF.1: Understand why a 5.NF.1:Framework, Add and Standard 3.NF.2 should serve as an opportunity a fraction 1/b as the fraction a/b is equivalent to subtract fractionsfor withinquantity formed by focus: a fraction (n × a)/(n × b) unlike denominators depth 4.NF.6: Use Decimal Notations for Fractions with Denominators 10 or 100 4.NF.7: Compare Two Decimals to Hundredths 3.NF.3D: Compare two fractions with the same numerator or denominator According to the PARCC Model Content Framework, Standard 4.NF.1 & 4.NF.3 should serve as opportunities for in-depth focus: 4.NF.1: “Extending fraction equivalence to the general case is necessary to extend arithmetic from whole numbers to fractions and decimals.” N/A 4.NF.3: “This standard represents an important step in the multi-grade progression for addition and subtraction of fractions. Students extend their prior understanding of addition and subtraction to add and subtract fractions with like denominators by thinking of adding or subtracting so many unit fractions.” According to the PARCC Model Content Framework, The key advance in fraction concepts between fourth and fifth grade is: “Students use their understanding of fraction equivalence and their skill in generating equivalent fractions as a strategy to add and subtract fractions, including fractions with unlike denominators.” N/A 4.NF.2: Compare two fractions with different numerators and different denominators. Record the results of comparisons with symbols >, =, or < 5.NBT.3: Read, write and compare decimals to thousandths 4.NF.6: Use decimal notation for fractions with denominators 10 or 100. For example, rewrite 0.62 as 62/100; describe a length as 0.62 meters; locate 0.62 on a number line diagram 4.NF.7: Compare two decimals to hundredths by reasoning about their size. Recognize that comparisons are valid only when the two decimals refer to the same whole. Record the results of comparisons with the symbols >, =, or <, and justify the conclusions, e.g., by using a visual model. 5.NF.1: Add and subtract fractions with unlike denominators. 5.NF.3: Interpret a fraction as division of the numerator by the denominator (a/b = a ÷ 5.NBT.3: Read, write, and compare decimals to thousandths. a. Read and write decimals to thousandths using base-ten numerals, number names, and expanded form, e.g., 347.392 = 3 × 100 + 4 × 10 + 7 × 1 + 3 × (1/10) + 9 × (1/100) + 2 × (1/1000). b. Compare two decimals to thousandths based on meanings of the digits in each place, using >, =, and < 3 | P a g e Big Ideas • • • • • Fractions are numbers with special names that tell how many parts of that size are needed to make the whole, written in the form a/b (when b is not zero). A fraction does not say anything about the size of the whole or the size of the parts; it tells us only about the relationship between the whole and each part Decimal comparisons are only valid if the whole is the same size. There are multiple ways to compare decimals (place value positions, visual models, estimation) just as there are multiple ways to compare whole numbers. Proper fractions have values less than one whole, as do numbers to the right of a decimal When partitioning a whole into more equal shares, the parts become smaller (i.e. eighths are smaller than fifths) 4 | P a g e Students Will… Know/Understand • • • • • • • • • • • • • • Mixed numbers and improper fractions can be used interchangeably. Fractions with different wholes and parts can be equivalent, which means to have the same value The denominator represents the number of equal parts that compose the whole The numerator represents the number of parts being observed relative to the whole That the more parts a whole is divided into (i.e. the larger the denominator), the smaller the size of each part. Conversely, the fewer parts a whole is divided into (i.e. the smaller the denominator) the bigger the size of each part comparisons of fractions are only valid when the fractions refer to the same whole that when you multiply the numerator and denominator by the same factor it does not change the value of the fraction. How the identity property of multiplication is employed to create equivalent fractions [(n*a)/(n*b) = na/nb]. A fractional quantity can be subdivided into an infinite number of equal pieces while maintaining the original fractional quantity, e.g., 1/2 can be subdivided into 2/4, 4/8 and so on. Those subdivisions are called equivalent fractions. That b/b = 1 whole. that measurement quantities can be represented using diagrams such as number lines (with appropriate measurement scale). Like fractions, decimal values can only be compared when they refer to the same whole. the meanings of the symbols >, <, and =.. that fractions with denominators of 10 or 100 are Be Skilled At… • • • • • • • • • • • • • • • Representing and reading proper fractions, improper fractions, and mixed numbers in multiple ways. Using fraction models (e.g., objects, drawings, manipulatives, etc.) to show equivalent fractions. Creating equivalent fractions Decomposing fractions into a sum of fractions with the same denominator in more than one-way, e.g., 3/8 = 1/8 + 2/8. Comparing fractions using concrete and pictorial models, as well as reasoning about their sizes compared to common benchmarks Using mixed numbers and improper fractions interchangeably. Comparing fractions and express their relationships using the symbols, >, <, or =. Determining the greatest common factor or least common multiple of two given numbers Recognizing when two fractions are equivalent. Generating an equivalent fraction to another fraction by multiplying the fraction by a factor Constructing models of equivalent fractions using manipulatives such as paper, color tiles, fractions strips, and fraction circles. Decomposing and recording fractions into a sum of fractions with the same denominator in more than one way. Representing fraction a/b with a > 1 using visual models. Comparing decimals according to their size and record the results of the comparison using the symbols >, <, and =. Explaining the relationship between a fraction with a denominator of 10 and a fraction with a • • • Every fraction is equivalent to an infinite number of other fractions A fraction can be written in decimal notation and a decimal can be written in fraction notation A decimal and fraction can represent the same value on the number line (this means they are equivalent) • • • • called tenths or hundredths respectively, and can be written in decimal form that decimals can be written as fractions and fractions as decimals that fractions with a denominator 10 or 100 are called decimal fractions. that comparisons are only valid when the two decimals refer to the same whole. Students must be able to relate a decimal to a whole number. • • • • • • • • How are fractions and decimals related? What is the relationship between a fraction with a denominator of 10 to another fraction with a denominator of 100? 5 | P a g e denominator of 100. Students express a fraction with a denominator of 10 or 100 as an equivalent decimal read and write decimals through the hundredths. generate equivalent decimal fractions (e.g. 4/10=40/100). properly name fractions (e.g., 7/10 is "seven tenths"). write decimal fractions as decimals in a variety of situations. For example, rewrite 0.62 as 62/100; describe a length as 0.62 meters; locate 0.62 on a number line diagram. compare two decimals to hundredths by reasoning about their size. justify conclusions about the comparison of decimals using visual models (including area models, decimal grids, decimal circles, number lines, and meter sticks) and other methods. Unit Sequence 1 Student Friendly Objective SWBAT… Decompose a whole number into various fractional parts. Describe what happens to the size of each part as the number of total parts increases or decreases. • 6 | P a g e Key Points/ Teaching Tips • Key Points: 1) Fractions are values on a number line 2) Fractions are a special type of number that tells how many parts of a certain size are needed to make the whole and that are written in form a/b. 3) A fraction by itself tells us nothing about the actual size/value – it only tells us the size of each part relative to the whole • Students should decompose a variety of whole numbers (beginning with 1) using all of the different unit fractions (1/2, 1/3, ¼, 1/5 and so on) using concrete manipulatives Important: Students must become comfortable with the various notations for special cases, i.e.: The number 1 can be written as 1/1 or as any whole number over the same number of total parts (3/3, 4/4, 5/5, etc.) Any whole number can be written in fraction form as that number over 1 (i.e. 2/1, 3/1, 4/1, etc._ • Provide an opportunity for students to make observations about what happens to the size of each part as the total number of parts increases or decreases (i.e. dividing one whole into eighths yields smaller parts than dividing that same whole into fourths) Exit Ticket 1) How many eighths are in one whole? Explain and draw a visual to justify your thinking: Model Instructional Resources My Math Chapter 8: Am I Ready? Page 477 “Pattern Block Fractions” (Appendix C) Written Reasoning 2) How many fourths are in 3/1? Draw a visual to justify your thinking 3) If I ate 5/5 of a candy bar does that mean I ate: a. 5 candy bars b. 1 candy bar c. 5 pieces of a candy bar, with 5 pieces left over d. 1 of 5 pieces of a candy bar Explain, then draw a visual model to support your thinking: 2 Model fractions as part of a Given a part, find the whole and vice whole in real world scenarios versa using area or region models Example to model with (using any of the models illustrated below): Pete painted 4/8 of a rectangle green. He painted 1/8 of the same rectangle blue. Pete painted the rest of the rectangle red. (a) What fraction of the rectangle did Pete paint red? Show your work. (b) Draw a rectangle to model the amount of each color Pete used. Divide the rectangle into equal parts, and label the parts G for green, B for blue, and R for red. 1) The rectangle below represents 1/5 of Activity for guided a whole. As precisely as possible, draw a practice and/or inquiryrectangle that represents the whole. (1 pt) based learning to start the lesson: “Their Fair Shares” (Appendix C) 2) The square below represents ¾ of a whole. As precisely as possible, draw a square that represents the whole. (1 pt) 3) Five friends ordered 3 large sandwiches: (c) The rectangle below represents 2/5 of a whole rectangle. What must the whole look like? • • Provide an opportunity for students to explore relative sizes/values of fractions while working with area models: http://learnzillion.com/lessons/104compare-fractions-using-an-arealmodel James ate 3/4 of a sandwich. Katya ate 1/4 of a sandwich. Ramon ate 3/4 of a sandwich. Sienna ate 2/4 of a sandwich. Emphasis on this lesson is the different physical and visual representations of fractions in a real world setting using area models (refer to picture of examples of acceptable area models) Also provide students with hands on opportunities in guided practice to build a complete whole when given a part (i.e. refer to questions 1-2 on the exit ticket) – you should give a visual of part of a set and allow students time to work with manipulatives to create that part and then determine what the whole must be) Use visual models to determine how much sandwich is left for Oscar 7 | P a g e 3 Model fractions as part of a set in real world scenarios using set models Given a part find the set; given the set, find the part 1) Alicia opened her piggy bank and counted the coins inside. Here is what she found: 22 pennies 5 nickels 5 dimes 8 quarters “Attribute Pieces Activity Sheet” (Appendix C) What fraction of the coins in the piggy bank are dimes? https://illuminations.nct m.org/lesson.aspx?id=1 301 Use four different manipulative (or different colors) to represent the different parts that make up this set to answer the question. ( 3 pts) MP.2 & MP 4 2) For each of the problems below, draw a visual of the whole set in order to justify your thinking. Provide students an opportunity to discuss the relative sizes/values of fractions when working with set models: http://learnzillion.com/lessons/105compare-fractions-using-a-set-model • • https://illuminations.nct m.org/lesson.aspx?id=1 298 https://illuminations.nct m.org/lesson.aspx?id=1 305 *Note: the resources provided here are some ideas of how you may approach this lesson – feel free to modify as necessary. The “attribute pieces” resource included in Appendix C corresponds with the lesson listed in the first link 3.) Explain your reasoning for what a “fraction as part of a set” means using precise language and vocabulary. 8 | P a g e 4 Decompose fractions into their sum of unit fractions and in at least one other way using area models and tape diagrams • • • 5 Decompose non-unit fractions and represent them as a whole number times a unit fraction using tape diagrams 9 | P a g e Sum of unit fractions example: ( ¾ = ¼ + ¼ + ¼). Other Examples:4/5 = 1/5 + 3/5 2/5 + 2/5 1/5 + 1/5 + 2/5 1/5 + 1/5 + 1/5 + 1/5 Students should continue connecting their decompositions to visual/area models Be sure to include examples of whole numbers and the number 1 written in fraction form (examples: 3/3 and 3/1) Complete the chart below by “Engage NY decomposing each fraction in at least two Lesson 5.1 and 5.2” different ways. For each way, draw a (Appendix C) visual that illustrates how you decomposed it and then write the sum of http://learnzillion.com/l its parts: essons/112-decomposeFraction As a sum of Way #2 to fractions-usingunit Decompose addition fractions 7 /8 5 /9 Engage NY Module 5 Lesson 3 (Appendix C) 6 Attend to precision when plotting fractions on a number line. Describe the location of various fractions on a number line relative to common benchmarks (0, ¼, ½, ¾ and 1 whole) • • • • Reinforce the big idea that a fraction is a number on the number line and that a proper fraction falls between the whole numbers 0 and 1 After students build their own fractions following the fraction kit task, provide them with a number line that is the same size as the fraction strips they created. Students must line up each of their fraction strips with the number line to identify and label its precise location on the number line Model the various ways to decompose a proper fraction using a number line in reference to the benchmark fractions Modify as necessary to remediate or extend fraction concepts and to build off the previous lessons regarding decomposing fractions and whole numbers 1) Plot the fraction 3/8 on the number line below: Fraction Kits (Appendix C) *modify resource to meet objective and b.) Describe the value of the fraction by include number lines explaining its location on the number line (see teaching tips between benchmark fractions: notes) This fraction can be found on the number line between ___________ and __________, and is closest to ____________. 2.) Use different colored pencils to illustrate the different ways you can decompose 5/7 on a number line: *Materials needed: scissors, 8 different colors of construction paper and two pieces of white paper (to use for the number lines) As a sum of its unit fractions: As a sum of 2/7 + ____ As a sum of _______ + _________ b.) Describe the value of the fraction by explaining its location on the number line between benchmark fractions: This fraction can be found on the number line between ___________ and __________, and is closest to ____________. 10 | P a g e