Unit 2

Place Value and Problem Solving using Addition and Subtraction with Units of Measure

 

Grade 3

Math

Unit Length and Description:

 

30 days

 

In Unit 2, students use place value understanding to round whole numbers. Students add and subtract using strategies and algorithms.  Students solve one- and two-step word problems involving addition and subtraction, units of measure and telling time. Students continue to practice fluency of basic facts involving factors of 2, 3, 4, 5, and 10 and their related division facts.

 

Standards:

 

Additional Cluster Standards

Use place value understanding and properties of operations to perform multi-digit arithmetic.

3.NBT.1

Use place value understanding to round whole numbers to the nearest 10 or 100.

3.NBT.2

Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

Major Cluster Standards

Solve problems involving the four operations, and identify and explain patterns in arithmetic.

3.OA.D.9

Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations.

Solve problems involving measurement and estimation of intervals of time, liquid volumes, and masses of objects.

3.MD.1

Tell and write time to the nearest minute and measure time intervals in minutes. Solve word problems involving addition and subtraction of time intervals in minutes, e.g., by representing the problem on a number line diagram.

3.MD.2

Measure and estimate liquid volumes and masses of objects using standard units of grams (g), kilograms (kg), and liters (l). Add, subtract, multiply, or divide to solve one-step word problems involving masses or volumes that are given in the same units, e.g., by using drawings (such as a beaker with a measurement scale) to represent the problem.

Mathematical Practices

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.

 

Instructional Outcomes

 

3.NBT.1: Use place value understanding to round whole numbers to the nearest 10 or 100.

  • I can define “round or rounding” in relation to place value.
  • I can round a whole number to the nearest 10.
  • I can round a whole number to the nearest 100.

 

3.NBT.2: Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

  • I can identify strategies for adding within 1000.
  • I can identify strategies for subtracting within 1000.
  • I can fluently add within 1000.
  • I can fluently subtract within 1000.

 

3.OA.D.9: Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations.

  • I can identify patterns.
  • I can explain rules for a pattern using properties of operations.
  • I can explain relationships between the numbers in a pattern.

 

3.MD.1: Tell and write time to the nearest minute and measure time intervals in minutes. Solve word problems involving addition and subtraction of time intervals in minutes, e.g., by representing the problem on a number line diagram.

  • I can recognize minute marks on analog clock face and minute position on digital clock face.
  • I can tell and write time to the nearest minute.
  • I can compare an analog clock face with a number line.
  • I can use a number line to add and subtract time.
  • I can solve word problems related to adding and subtracting minutes.

 

3.MD.2: Measure and estimate liquid volumes and masses of objects using standard units of grams (g), kilograms (kg), and liters (l). Add, subtract, multiply, or divide to solve one-step word problems involving masses or volumes that are given in the same units, e.g., by using drawings (such as a beaker with a measurement scale) to represent the problem.

  • I can add, subtract, multiply and divide units of liters, grams, and kilograms.
  • I can use strategies to represent a word problem involving liquid volume or mass.
  • I can solve one step word problems involving masses given in the same units.
  • I can solve one step word problems involving liquid volume given in the same units (eg. by using cups, pints, quarts, and gallons).

 

 

 

 

Enduring Understandings:

 

Place Value and Rounding…

        Estimation helps us see whether or not our answers are reasonable.

        Using rounding is an appropriate estimation strategy for solving problems and estimating.

 

Addition and Subtraction…

        Addition and subtraction are inverse operations.

        Addition means the joining of two or more sets that may or may not be the same size. The counting up strategy can be used to make change.

        Subtraction denotes finding the difference between sets or comparing sets.

 

Measurement:

·         The duration of an event is called elapsed time and it can be measured.

·         Mass and volume are important parts of everyday life and can determined a variety of ways.

 

Essential Questions:

 

·         Does rounding a number change its value relative to other numbers?

·         How are addition and subtraction alike and how are they different?

·         How can I show what I know about addition and subtraction, problem solving, and estimation?

·         How can I use what I know about addition and subtraction to help me solve problems?

·         What type of situations do we add and subtract?

·         How can I use what I understand about money to solve word problems?

·         How do we round numbers to the nearest ten or hundred?

·         How is rounding used in everyday life?

·         What strategies can I use to help me tell and write time to the nearest minute and measure time intervals in minutes?

·         Why is measurement important in my everyday life?