Topic Six Subtraction Facts to 20

Pacing (Duration of Unit):
-

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.OA.1 Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.
  • 1.OA.4 Understand subtraction as an unknown-addend problem.
  • 1.OA.6 Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use mental strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 – 4 = 13 – 3 – 1 = 10 – 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 – 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).
  • 1.OA.8 Determine the unknown whole number in an addition or subtraction equation relating three whole numbers

Student "I Can" Statements:

  • I can use strategies to solve addition word problems.
  • I can use strategies to solve subtraction word problems.
  • I can use an addition fact to help me answer a subtraction problem.
  • I can add facts within 20.
  • I can subtract facts within 20.
  • I can tell the missing number in an addition or subtraction problem.


Prerequisite Standards:

  • K.OA.2 Solve addition and subtraction word problems, and add and subtract within 10, e.g., by using objects or drawings to represent the problem.
  • K.OA.3 Decompose numbers less than or equal to 10 into pairs in more than one way, e.g., by using objects or drawings, and record each decomposition by a drawing or equation (e.g., 5 = 2 + 3 and 5 = 4 + 1).
  • K.OA.5 Fluently add and subtract within 5.
  • 1.OA.1 Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.
Big Ideas:

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

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

  • What other strategies can be used to find subtraction facts?
Students will know...

  • Subtraction facts with teen numbers can be simplified by making use of the numbers relationships to 10.
  • Addition and subtraction have an inverse relationship. The inverse relationship between addition and subtraction can be used to find subtraction facts: every subtraction fact has a related addition fact.
  • Information in a problem can often be shown using a picture or diagram and used to understand and solve the problem. Some problems can be solved by writing and completing a number sentence or equation.


Vocabulary:

related facts
fact family
Students will be skilled at...

  • Making 10 to subtract.
  • Making 10 to solve subtraction story problems.
  • Finding subtraction facts to 18 and learn the relationship between addition and subtraction.
  • Using a part-part-whole model to find the subtraction facts and addition facts in a fact family.
  • Using a related addition fact to find the missing part in a subtraction problem.
  • Using related addition facts to solve subtraction problems.
  • Drawing pictures and writing number sentences to solve addition and subtraction story problems.

Assessment Evidence

Performance Assessment:
Other Evidence:

Learning Plan

Learning Activities:
6-1 Subtraction facts with teen numbers can be simplified by making use of the numbers relationships to 10.
6-2 Subtraction facts with teen numbers can be simplified by making use of the numbers relationships to 10.
6-3 Addition and subtraction have an inverse relationship. The inverse relationship between addition and subtraction can be used to find subtraction facts: every subtraction fact has a related addition fact.
6-4 Addition and subtraction have an inverse relationship. The inverse relationship between addition and subtraction can be used to find subtraction facts: every subtraction fact has a related addition fact.
6-5 Addition and subtraction have an inverse relationship. The inverse relationship between addition and subtraction can be used to find subtraction facts: every subtraction fact has a related addition fact.
6-6 Addition and subtraction have an inverse relationship. The inverse relationship between addition and subtraction can be used to find subtraction facts: every subtraction fact has a related addition fact.
6-7 Information in a problem can often be shown using a picture or diagram and used to understand and solve the problem. Some problems can be solved by writing and completing a number sentence or equation.
Resources: