Topic 11:Use Models And Strategies To Subtract Tens

Pacing (Duration of Unit): 7 Lessons

Desired Results

Transfer:
1. Makes 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.
Established Goals:
  • 1.NBT.5 Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
  • 1.NBT.6 Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

Student "I Can" Statements:

  • I can find 10 more or 10 less in my head.
  • I can use different strategies to subtract multiples of 10 (10-90) from numbers under 100 , write the matching number sentence and explain my strategy.

Prerequisite Standards:

  • K.CC.1: Count to 100 by ones and by tens.
  • K.CC.2: Count forward beginning from a given number within the known sequence (instead of having to begin at 1).
Big Ideas:

Equivalence
Any number, measure, numerical expression, algebraic expression, or equation can be represented in an infinite number of ways that have the same value.

Numbers and the Number Line
The set of real numbers is infinite and ordered. Whole numbers, integers, and fractions are real numbers. Each real number can be associated with a unique point on the number line.

Number Uses, Clarification, and Representation
Numbers can be used for different purposes, and numbers can be classified and represented in different ways.

The Base-Ten Numeration System
The base-ten numeration system is a scheme for recording numbers using digits 0-9, groups of ten, and place value.

Operation Meanings & Relationships
There are multiple interpretations of addition, subtraction, multiplication, and division of rational numbers and each operation is related to other operations.

Basic Facts and Algorithms
There is more than one algorithm for each of the operations with rational numbers. Some strategies for basic facts and most algorithms for operations with rational numbers, both mental math and paper and pencil, use equivalence to transform calculations into simpler ones.

Patterns, Relations, and Functions
Relationships can be described and generalizations made for mathematical situations that have numbers or objects that repeat in predictable ways. For some relationships, mathematical expressions and equations can be used to describe how members of one set are related to members of a second set.

Practices, Processes, and Proficiencies
Mathematics content and practices can be applied to solve problems.
Essential Questions:

  • How can I use what I know about subtraction to subtract tens?
Students will know...

  • Subtracting a multiple of 10 from another multiple of 10 is similar to subtracting numbers less than 10.
  • Subtracting multiples of 10 is like counting back by 10s. You can show how to subtract a multiple of 10 from another multiple of 10 on a hundred chart.
  • Subtracting multiples of 10 is like counting back by 10s. You can show how to subtract a multiple of 10 from another multiple of 10 on an open number line.
  • Addition and subtraction have an inverse relationship. This relationship can be used to solve subtraction equations; every subtraction equation has a related addition equation.
  • When subtracting tens from a two-digit number, the tens digit changes. The ones digit remains unchanged.
  • You can use different strategies to solve subtraction problems.
  • Mathematicians use math they know to show and solve problems.


Vocabulary:

n/a
Students will be skilled at...

  • Using models to subtract tens.
  • Using a hundred chart to subtract a multiple of 10 from another multiple of 10.
  • Using an open number line to solve subtraction problems.
  • Using addition to subtract tens.
  • Using mental math to subtract ten from a two-digit number.
  • Using different strategies to subtract.
  • Modeling thinking to solve problems.

Assessment Evidence

Performance Assessment:
Other Evidence:

Formative Assessments:

Learning Plan

Learning Activities:

11-1 Subtracting a multiple of 10 from another multiple of 10 is similar to subtracting numbers less than 10.
11-2 Subtracting multiples of 10 is like counting back by 10s. You can show how to subtract a multiple of 10 from another multiple of 10 on a hundred chart.
11-3 Subtracting multiples of 10 is like counting back by 10s. You can show how to subtract a multiple of 10 from another multiple of 10 on an open number line.
11-4 Addition and subtraction have an inverse relationship. This relationship can be used to solve subtraction equations; every subtraction equation has a related addition equation.
11-5 When subtracting tens from a two-digit number, the tens digit changes. The ones digit remains unchanged.
11-6 You can use different strategies to solve subtraction problems.
11-7 Mathematicians use math they know to show and solve problems.
Resources:

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