• # Elementary Mathematics Grade 3 Unit 8

Subject: Mathematics
Timeline: 18 days
Unit 8 Title: Problem Solving with Units of Measurement (Time, Weight, and Liquid)

Unit Overview:

This unit will give the opportunity for students to write and tell time to the hour and minute using an analog clock.  They will also measure elapsed time intervals in minutes.  Students will be solving word problems that involve addition and subtraction of time intervals in minutes.  Students will make reasonable estimates about the mass and liquid volume of objects, using both the standard (customary) and metric systems.  They will be able to use all 4 operations to solve one step problems involving time, mass, and liquid volume within the same unit.

Unit Objectives:

At the end of this unit, all students must be able read, write, and tell time using digital and analog clocks. They will also have to be able to understand and give equivalent names for time. Students will also have to be able to solve problems involving elapsed time. They must be able to measure and estimate mass and liquid volume of objects using standard (customary) and metric units.  They must be able to apply measurement concepts to solve problems involving time, mass, and liquid volume.

Focus Standards:

PA.CCSS.Math.Content.CC.2.4.3.A.1 Solve problems involving measurement and estimation of temperature, liquid volume, mass or length.  (3.MD.2)
PA.CCSS.Math.Content.CC.2.4.3.A.2 Tell and write time to the nearest minute and solve problems by calculating time intervals.  (3.MD.1)

Mathematical Practice Standards:

#1 Make sense of problems and persevere in solving them.

Mathematically proficient students start by explaining to themselves the meaning of a problem and look for an entry point to its solution. They then plan a solution pathway rather than jumping into a solution attempt.  They monitor and evaluate their progress and change course, if needed.  Students might rely on using concrete objects or pictures to help conceptualize and solve a problem.  They then check their answers to problems using a different method, and continually ask themselves, “Does this make sense?”  These students can also understand the approaches of others to solving complex problems and identify correspondences between different approaches.

#2 Reason abstractly and quantitatively.

Mathematically proficient students make sense of quantities and their relationships in problem situations.  They bring two complementary abilities to bear on problems, the ability to decontextualize-to abstract the given situation and represent it symbolically and manipulate the representing symbols as if they have a life of their own, without necessarily attending to their referents and contextualize-to pause as needed to during the manipulation process in order to probe into the referents for the symbols involved.

#3 Construct viable arguments and critique the reasoning of others.

Mathematically proficient students understand and use states assumptions, definitions, and previously established results in constructing arguments. They make a statement that they believe to be true but not yet proved and then build a progression of statements to explore its truth. They justify their conclusions, communicate them to others and respond to the arguments of others. Elementary students can construct arguments using concrete referents such as objects, drawings, diagrams, and actions.

#4 Model with mathematics.

Mathematically proficient students can apply the mathematics they know to solve problems arising in everyday life, society, and the workplace. In early grades, this might be as simple as writing an addition equation to describe a situation.

#5 Use appropriate tools strategically.

Mathematically proficient students consider the available tools when solving a mathematical problem. These tools might include pencil and paper, concrete models, a ruler, a protractor, or a calculator. Proficient students are sufficiently familiar with tools appropriate for their grade to make sound decisions about when each of these tools might be helpful, recognizing both the insight to be gained and their limitations.

#6 Attend to Precision.

Mathematically proficient students try to communicate precisely to others.  They use clear definitions in discussions with others and in their own reasoning.  They state the meaning of the symbols they choose, including the equals sign, consistently and appropriately.  They calculate accurately and efficiently and give carefully formulated explanations to each other.

#7  Look for and make use of structure.

Mathematically proficient students look closely to discern a pattern or structure. Young students, for example, might notice that three and seven more is the same amount as seven and three more, or they may sort a collection of shapes according to how many sides the shapes have.

# 8 Look for and express regularity in repeated reasoning.

Mathematically proficient students notice if calculations are repeated, and look both for general methods and for shortcuts... They continually evaluate the reasonableness of their intermediate results.

Concepts - Students will know:
• On an analog clock, each line represents a minute within that 60 minute hour
• Elapsed time is the time that elapsed or went by during a task
• Mass describes the weight of an object.
• Liquid volume (also called capacity) describes how much space a liquid takes up in an object.
• Metric units include liters and milliliters, grams, and kilograms.
• Standard units include ounces, pounds, and tons, and gallons, quarts, pints, and cups.
Competencies -Students will be able to:
• Tell and write time to the nearest minute
• Solve problems by calculating time intervals
• Solve word problems involving addition and subtraction of time intervals in minutes, e.g., by representing the problem on a number line diagram
• Measure and estimate the mass of different objects using both standard and metric units.
• Measure and estimate the liquid volume (capacity) of different objects using both standard and metric units.
• Solve problems using all 4 operations involving time, mass, and liquid volume.

Assessments:
• Unit 8 Progress Check
• Daily RSA

Elements of Instruction:

Students leaving a second grade Common Core classroom have learned to tell time within 5 minutes using am and pm.  They have no experience with weight and volume.

Differentiation:

Each lesson has differentiation options for each portion of the lesson. Additional differentiation options are listed with directions and student masters in the Teacher’s Guide.

Interdisciplinary Connections:

None