Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = ? – 3, 6 + 6 = ?.

Quarter 3

Quarter 4

Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = ? – 3, 6 + 6 = ?.

Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = ? – 3, 6 + 6 = ?.

Enduring Understanding

Mathematical operations are used in solving problems in which a new value is produced from one or more values.
Algebraic thinking involves choosing, combining, and applying effective strategies for answering quantitative questions.

Essential Questions

In what ways can operations affect numbers?
How can different strategies be helpful when solving a problem?

This standard is critical in developing students' problem solving skills, algebraic foundations, and understanding of addition and subtraction. There are two types of part-part-whole problems. In one type, the sizes of both parts are given and the student has to find the whole. Or students are given the size of one part and the size of the whole, and they need to find the size of the missing part. This concept is an extension of decomposing of numbers and students will use their understanding of decomposition of numbers when finding the missing part. Students may need to use counters to see how a number can be broken up into different parts before moving to the more abstract representation.

Rich Tasks for Multiple Means of Engagement, Expression, and Representation (UDL)

I Wish I Had (Van de Walle, K-3, p 51). Hold out a bar of connecting cubes, a ten-frame or dot plate showing 6 or less. Say, "I have this many, but I wish I had six." The children respond with the part that is needed to make six. Counting on can be used to check. The game can focus on a single whole ( like six) or the "I Wish I Had" number can change each time.

Other Instructional Resources:
Van de Walle, K-3 Activity 2.19 Missing-Part Cards, page 50
Van de Walle, K-3 Activity 4.14 Missing Number Cards page 110

Rich Problem:
Aaron started with the number 10 on his calculator and ended with 20 without clearing the calculator display. Using a calculator, investigate and record the ways that Aaron might have used to get from 10 to 20.

Insert each of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 in the right spot. Each digit may only be used once. (Small, Good Questions, Great Ways to Differentiate Mathematics Instruction, p 43).
9 + _ = 1_ _ + 4 = 1 _
1 _ - 8 = 4
_ + _ = _ _
_ + 2 + 7

Journal Prompt:

Josie had to find a number to go in the blank for this problem:
6 + __ = 14
Find the missing number. Describe how you found the answer. Or draw a picture that shows how you found the answer.

## Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = ? – 3, 6 + 6 = ?.

Quarter 3Quarter 4

Mathematical operations are used in solving problems in which a new value is produced from one or more values.Enduring UnderstandingAlgebraic thinking involves choosing, combining, and applying effective strategies for answering quantitative questions.

In what ways can operations affect numbers?Essential QuestionsHow can different strategies be helpful when solving a problem?

Addition, add, subtraction, subtract, equationVocabulary (online dictionary, HCPSS Vocabulary Cards)

This standard is critical in developing students' problem solving skills, algebraic foundations, and understanding of addition and subtraction. There are two types of part-part-whole problems. In one type, the sizes of both parts are given and the student has to find the whole. Or students are given the size of one part and the size of the whole, and they need to find the size of the missing part. This concept is an extension of decomposing of numbers and students will use their understanding of decomposition of numbers when finding the missing part. Students may need to use counters to see how a number can be broken up into different parts before moving to the more abstract representation.About the MathIllustrative Mathematics Project: Finding Missing Numbers

## Rich Tasks for Multiple Means of Engagement, Expression, and Representation (UDL)

IWish I Had (Van de Walle, K-3, p 51). Hold out a bar of connecting cubes, a ten-frame or dot plate showing 6 or less. Say, "I have this many, but I wish I had six." The children respond with the part that is needed to make six. Counting on can be used to check. The game can focus on a single whole ( like six) or the "I Wish I Had" number can change each time.Other Instructional Resources:Van de Walle, K-3 Activity 2.19 Missing-Part Cards, page 50

Van de Walle, K-3 Activity 4.14 Missing Number Cards page 110

Rich Problem:Aaron started with the number 10 on his calculator and ended with 20 without clearing the calculator display. Using a calculator, investigate and record the ways that Aaron might have used to get from 10 to 20.

Insert each of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 in the right spot. Each digit may only be used once. (Small, Good Questions, Great Ways to Differentiate Mathematics Instruction, p 43).

9 +

_ = 1__ + 4 = 1_1

_ - 8 = 4_ +

_ =_ __ + 2 + 7

Josie had to find a number to go in the blank for this problem:Journal Prompt:6 + __ = 14

Find the missing number. Describe how you found the answer. Or draw a picture that shows how you found the answer.

Print ResourcesRead It! Draw It! Solve It! Grade 1

(140, 158, 160, 162)

Math Intervention: Building Number Power K-2

(111-121)

Groundworks Algebraic Thinking Grade 1

(64-87)

Web Resources:Games and CentersLessonsStudent ResourcesVideo SegmentsFind the Missing Number

Online Games

Stop the Clock

Addition +

Missing Addend

Balance

Block Pounds

Try For Five

Modeling Subtraction

Lesson SeedsTeaching Fact Families

Illustrative Mathematics Project

Finding Missing Numbers

Fact Family CardsFunction Table TemplateMagic Pot Workmat

Connecting Children's Literature:Click on the books for additional activities.Two Of EverythingBy: Lily Toy Hong

Safari Park

By: Stuart J. Murphy

## Questions/Comments:

Contact John SanGiovanni at jsangiovanni@hcpss.org.Use and Sharing of HCPSS Website and Resources:Howard County Public Schools Office of Elementary Mathematics Curricular Projects has licensed this product under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.