Unit 6: Multiplication and Division: Application and Fluency within 100 April 15-May 30 (7 weeks)
3rd Grade Mathematics - InvestigationsUnit 6: Multiplication and Division: Application and Fluency within 100
Teacher Resource Guide /
2012 - 2013 /
In Grade 3, instructional time should focus on four critical areas:
- Developing understanding of multiplication and division and strategies for multiplication and division within 100;
Students develop an understanding of the meanings of multiplication and division of whole numbers through activities and problems involving equal-sized groups, arrays, and area models; multiplication is finding an unknown product, and division is finding an unknown factor in these situations.
- Developing understanding of fractions, especially unit fractions (fractions with a numerator of 1);
Students are able to use fractions to represent numbers equal to, less than, and greater than one. They solve problems that involve comparing fractions by using visual fraction models and strategies based on noticing equal numerators or denominators.
- Developing understanding of the structure of rectangular arrays and of area;
Students understand that rectangular arrays can be decomposed into identical rows or into identical columns. By decomposing rectangles into rectangular arrays of squares, students connect area to multiplication, and justify using multiplication to determine the area of a rectangle.
- Describing and analyzing two-dimensional shapes;
Students compare and classify shapes by their sides and angles, and connect these with definitions of shapes. They also relate their fraction work to geometry by expressing the area of part of a shape as a unit fraction of the whole.
3rd Grade 2011-2012Page 1
Unit 6: Multiplication and Division: Application and Fluency within 100 April 15-May 30 (7 weeks)
3rd Grade Mathematics 2012–2013
Unit / Time Frame / Test ByTRIMESTER 1 / 1: Addition and Subtraction
(Within 1,000) / 7 weeks / 8/27 – 10/12 / October 12
2: Multiplication and Division:
Models within 100 / 5 weeks / 10/15 – 11/16 / November 16
TRIMESTER 2 / 3: Geometry/Measurement / 4 weeks / 11/19-12/21 / December 21
4: Multiplication and Division:
Properties within 100 / 5 weeks / 1/2 – 2/8 / February 8
5: Fractions / 8 weeks / 2/11 – 4/12 / April 12
TRIMESTER 3
6: Multiplication and Division:
Application & Fluency within 100 / 7 weeks / 4/15 – 5/30 / May 30
Big Ideas / Essential Questions
Estimation is helpful in understating whether an answer is reasonable. / Why do we estimate?
Multiplication and division are inverse operations. / How are multiplication and division related?
Identifier / Standards / Mathematical Practices
STANDARDS / 3.OA.3
3.OA.1
3.OA.2
3.NBT.3 / Use multiplication and division within 100 to solve word problems in situations involving equal groups, arrays, and measurement quantities,
Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each.
Interpret whole-number quotients of whole numbers, e.g., interpret 56 ÷ 8 as the number of objects in each share when 56 objects are partitioned equally into 8 shares, or as a number of shares when 56 objects are partitioned into equal shares of 8 objects each.
Multiply one-digit whole numbers by multiples of 10 in the range 10–90 (e.g., 9 × 80, 5 × 60)using strategies based on place value and properties of operations. / 1) Make sense of problems and persevere in solving them.
2) Reason abstractly and quantitatively.
3) Construct viable arguments and critique the reasoning of others.
4) Model with mathematics.
5) Use appropriate tools strategically.
6) Attend to precision.
7) Look for and make use of structure.
8) Look for and express regularity in
repeated reasoning.
3.OA.7
3.OA.4
3.OA.5
3.OA.6
3.OA.9 / Fluently multiply and divide within 100, using strategies such as the relationship between multiplication and division (e.g., knowing that 8 × 5 = 40, one knows 40 ÷ 5 = 8) or properties of operations. By the end of Grade 3, know from memory all products of two one-digit numbers.
Determine the unknown whole number in a multiplication or division equation relating three whole numbers.
Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations. For example, observe that 4 times a number is always even, and explain why 4 times a number can be decomposed into two equal addends.
Understand division as an unknown-factor problem.
Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations.
3.OA.8 / Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.3
3rd Grade 2012-2013Page 1
Unit 6: Multiplication and Division: Application and Fluency within 100 April 15-May 30 (7 weeks)
Identifier / Standards / Bloom’s / Skills / ConceptsSTANDARDS / 3.OA.3
3.OA.1
3.OA.2
3.NBT.3 / Use multiplication and division within 100 to solve word problems in situations involving equal groups, arrays, and measurement quantities,
Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each.
Interpret whole-number quotients of whole numbers, e.g., interpret 56 ÷ 8 as the number of objects in each share when 56 objects are partitioned equally into 8 shares, or as a number of shares when 56 objects are partitioned into equal shares of 8 objects each.
Multiply one-digit whole numbers by multiples of 10 in the range 10–90 (e.g., 9 × 80, 5 × 60)using strategies based on place value and properties of operations. / Apply (3) / Solve (mult & div word problems w/in 100) / multiplication
division
equal groups
arrays
measurement quantities
3.OA.7
3.OA.4
3.OA.5
3.OA.6
3.OA.9 / Fluently multiply and divide within 100, using strategies such as the relationship between multiplication and division (e.g., knowing that 8 × 5 = 40, one knows 40 ÷ 5 = 8) or properties of operations. By the end of Grade 3, know from memory all products of two one-digit numbers.
Determine the unknown whole number in a multiplication or division equation relating three whole numbers.
Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations. For example, observe that 4 times a number is always even, and explain why 4 times a number can be decomposed into two equal addends.
Understand division as an unknown-factor problem.
Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations. / Apply (3) / Multiply & divide (fluently w/in 100) / factor
product
3.OA.8 / Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.3 / Apply (3)
Understand (2)
Evaluate (5) / Solve (two-step word problems using the four operations)
Represent (with equations)
Assess
(reasonableness) / equation
mental computation
estimation
rounding
Instructional Strategies for ALL STUDENTS
The final unit will focus on the most difficult facts along with multiplication and division in context (word problems).
Critical Reading for Teachers Before Instruction -
Teaching Student-Centered Mathematics Grades K-3, Van de WalleLovin, Pearson, 2006, p. 77-79 & p. 82-85 (Building resource, SPED)
Children’s Mathematics,Carpenter, Heinneman, 1999 (CGI year 1 text)
Teaching Multiplication and Division Simultaneously – Multiplication and division are taught separately in most traditional programs, with multiplication preceding division. It is important, however, to combine multiplication and division soon after multiplication has been introduced in order to help students see how they are related (Van de Walle, 2006).
Real-world context – For students to reach the level of rigor intended for the operations of addition and subtraction in the new Iowa Core, they must develop understanding of the operations within real-world contexts. A lesson built around word problems focuses on how students solve the problem. They may use words, pictures, and numbers to explain how they solved the problem and why they think they are correct. Allow students to use physical materials or drawings. Someone else should be able to understand how they solved the problem when looking at their paper.
Multiplication and Division problem types – There are four structures for multiplication and division problems: Equal Groups, Comparison, Partitive (How many in each group?), and Measurement (How many groups?). See page 9 of this guide for further explanation of the problem types. Students need regular opportunities to solve all of the different types of problems in order to reach the level of rigor described in the Iowa Core.
Use of models to build conceptual understanding of multiplication – Drawings, counters, unifix cubes, and number lines are typically used to represent multiplication concepts. It is essential for students to understand the relationship between addition and multiplication. (See examples of models below.) To make clear the connection to addition, early multiplication work should include writing an addition sentence and a multiplication sentence. It is not necessary to write the products, but rather write one sentence that expresses both concepts at once, for example, 3 + 3 + 3 + 3 = 3 x 4.
Routines/Meaningful Distributed Practice
Distributed Practice that is Meaningful and Purposeful
Practice is essential to learn mathematics. However, to be effective in improving student achievement, practice must be meaningful, purposeful, and distributed.
- Meaningful: Builds on and extends understanding
- Purposeful: Links to curriculum goals and targets an identified need based on multiple data sources
- Distributed: Consists of short periods of systematic practice distributed over a long period of time
Routines are an excellent way to achieve the mandate of Meaningful Distributed Practice outlined in the Iowa Core Curriculum. The skills presented during routines do not necessarily reinforce the lesson concept for that day. Routines may be used to address a need for small increments of exposure to a skill or review of skills already taught. Routine activities may be repeated several days in a row, allowing for a build-up of conceptual understanding, or can be visited and re-visited over a period of time. Routines can be inserted as the schedule allows; in short intervals throughout the day or as a lesson opener or closer. Selection of the routine should be made based on informal teacher observation and formative assessments.
Concepts taught through Meaningful Distributed Practice during Unit 6:
Skill / StandardRequired: These concepts align to the supporting standards in this unit
Apply properties of operations for multiplication and division / 3.OA.5
Understand division as an unknown-factor problem / 3.OA.6
Multiply by multiples of 10 / 3.NBT.3
Additional: These concepts are optional, based on student need
Addition and Subtraction / 3.NBT.2
Fraction concepts / 3.NF
Tell and write time / 3.MD.1
Graphing / 3.MD.3
Other skills students need to develop based on teacher observation and formative assessments.
Investigations Resources for Unit 6- Multiplication and Division within 100 (Fluency)
Instructional Plan / Resource / Standards
Addressed
Multiplication and division fact strategies from Math Resource Binder / 3.AO.3
3.AO.7
3.OA.8
3.0A1
3.0A.2
3.0A.4
3.0A.5
3.0A.6
3.0A.9
Additional Focus needed on:
- Multiply one-digit whole numbers by multiples of 10 in the range 10-90 (e.g., 9 x 80, 5 x 60) using strategies based on place value and properties of operations
Lesson Progression
Lessons / Teacher Directions / Standards
Addressed
Story Problem Bank / Every week you should do at least 2 but prefer 3 multi-step story problems. (Through the use of the multi-step story problems the students will get practice in all more than one operation.) And then one multiplication story problem and one division story problems each week. This will allow students the ability to differentiate between the different types of story problems. / 3.OA.3
3.OA.8
These activities are for conversation and practicing basic facts.
Multiplication Shapes / These activities focus on multiplication facts of 6. / 3.OA.3
3.OA.7
How Many Points
Marching Ants & Guitar Strings
There’s Always Another Way – 6’s
Making Snowmen / These activities focus on the relationship between 2, 4, and 8. / 3.OA.3
3.OA.7
A Closer Look at our Snowmen Facts
Thunder Cake (literature connection with Thunder Cake) / This activity focus on facts of 7 / 3.OA.3
3.OA.7
There’s Always Another Way – 9’s / These activities focus on facts of 9. / 3.OA.3
3.OA.7
Math Facts Column – 9’s
Plates of Meatballs (literature connection with Cloudy with a Chance of Meatballs)
These activities are for student practices to help them become more fluent at multiplication & Division
Capture – 6’s / These games practice facts of 6. / 3.OA.7
Ratio Race
Missing Numbers – 7’s / This game practice fact of 7. / 3.OA.7
Corners Spinners – 8’s / These games practice facts of 8’s. / 3.OA.7
Easy Eights
Missing Numbers – 8’s
Spaces -8’s
Crazy Eight
Corners spinners – 9’s / These games practice facts of 9’s. / 3.OA.7
Write to Divide – 9’s
Spinning Facts – 6, 7, 8, 9 / This game practices facts 6, 7, 8, 9 / 3.OA.7
3rd Grade 2012-2013Page 1
Unit 6: Multiplication and Division: Application and Fluency within 100 April 15-May 30 (7 weeks)
Table 2.Common multiplication and division situations.[1]
Iowa Core Mathematics, p. 93;
Unknown Product / Group Size Unknown("How many in each group?"
Division) / Number of Groups Unknown
("How many groups?" Division)
3 × 6 = ? / 3 × ? = 18, and 18 ÷ 3 = ? / ? × 6 = 18, and 18 ÷ 6 = ?
Equal
Groups / There are 3 bags with 6 plums in each bag. How many plums are there in all?
Measurement example. You need 3 lengths of string, each 6 inches long. How much string will you need altogether? / If 18 plums are shared equally into 3 bags, then how many plums will be in each bag?
Measurement example. You have 18 inches of string, which you will cut into 3 equal pieces. How long will each piece of string be? / If 18 plums are to be packed 6 to a bag, then how many bags are needed?
Measurement example. You have 18 inches of string, which you will cut into pieces that are 6 inches long. How many pieces of string will you have?
Arrays,4
Area5 / There are 3 rows of apples with 6 apples in each row. How many apples are there?
Area example. What is the area of a 3 cm by 6 cm rectangle? / If 18 apples are arranged into 3 equal rows, how many apples will be in each row?
Area example. A rectangle has area 18 square centimeters. If one side is 3 cm long, how long
is a side next to it? / If 18 apples are arranged into equal rows of 6 apples, how many rows will there be?
Area example. A rectangle has area 18 square centimeters. If one side is 6 cm long, how long
is a side next to it?
Compare / A blue hat costs $6. A red hat blue hat. How much does the red hat cost?
Measurement example. A rubber band is 6 cm long. How long will the rubber band be when it is stretched to be 3 times as long? / A red hat costs $18 and that is 3 times as much as a blue hat costs. How much does a blue hat cost?
Measurement example. A rubber band is stretched to be 18 cm long and that is 3 times as long as it was at first. How long was the rubber band at first? / A red hat costs $18 and a blue hat costs $6. How many times as much does the red hat cost as the blue hat?
Measurement example. A rubber band was 6 cm long at first. Now it is stretched to be 18 cm long. How many times as long is the rubber band now as it was at first?
General / a × b = ? / a × ? = p, and p ÷ a = ? / ? × b = p, and p ÷ b = ?
The first examples in each cell are examples of discrete things. These are easier for students and should be given before the measurement examples.
4The language in the array examples shows the easiest form of array problems. A harder form is to use the terms rows and columns: The apples in the grocery window are in 3 rows and 6 columns. How many apples are in there? Both forms are valuable.
5Area involves arrays of squares that have been pushed together so that there are no gaps or overlaps, so array problems include these especially important measurement situations.
3rd Grade 2012-2013Page 1
Unit 6: Multiplication and Division: Application and Fluency within 100 April 15-May 30 (7 weeks)
Story Problem Bank
Multi-step story problems
In the third grade Mrs. Smith’s class has 25 students, Mrs. Jones has 27 students and Mr. Perez has 28 students. If the tables in the lunchroom can seat 10 students per table, how many tables will the third graders need to eat lunch? (joining & division)
At family night we had 800 tickets, we sold 755 tickets. We put the rest of the tickets into envelopes with 5 in each envelope. How many envelopes do we need? (Separating & division)
We went to the movies last weekend. 3 adults and 4 children attended the movies. It cost $8 for each adult and $6 for each child. We also each got a popcorn and pop combo that cost$7 per combo. How much money did we spend at the movies? (Multiplication & addition)
I made 8 pans of chocolate cookies; on each pan I can put 8 cookies at once. I also made 9 pans of peanut butter cookies and I can put 8 cookies on each pan. I also made 7 pans of ginger snaps, were I can also put 8 cookies on each pan. How many cookies did I make all together? (Multiplication and addition)
I need 185 stickers. I have 7 sheets of smiley faces, with 9 smiley faces on each sheet. I also have 8 sheets of butterflies, with 9 on each sheet. How many more stickers do I still need?
My cell phone plan allows for 950 text messages. I went over and used 958 text messages. Each extra text message cost 5 cents. How much will my extra texts cost?
I counted 42 tires in the parking lot. In the parking lot there are cars that have 4 tires and motorcycles that each has 2 tires. How many cars and motorcycles are in the parking lot? (See how many different answers you can find.)
At the park I counted 56 legs. At the park there are humans who have 2 legs and dogs that have 4 legs. How many humans and dogs are in the park? (See how many different answers you can find.)
I made 445 cookies. The third graders ate 396 cookies. With the left over cookies I put them in baggies with 7 cookies in each baggie. How many baggies do I need?
I bought 56 markers. They came in packages of 8. Each package cost $3. How much money did I spend on markers?
The lunch cooks made 9 pans of pizza. Each pizza is cut up into a 5 by 4 array. The students ate 146 pieces of pizza. How many pieces of pizza are left?
We were having breadsticks for lunch today. We had 435 breadsticks. The second and third graders ate 399 breadsticks. One serving of breadsticks is 3 breadsticks. How many servings of breadsticks are left?
I have 4 boxes of tennis balls. In each box there are 5 tennis ball containers. In each container there are 3 tennis balls. How many tennis balls are in all 4 boxes?
Mr. Nick sharpened 145 pencils. Mrs. Stone sharpened 179 pencils. They need 489 pencils sharpened, how many more do they need to sharpen?