Strand: OPERATIONS AND ALGEBRAIC THINKING (2.OA)

Represent and solve problems involving addition and subtraction (Standard 2.OA.1). Fluently add and subtract within 20 (Standard 2.OA.2) and work with equal groups of objects to gain foundations for multiplication (Standards 2.OA.3–4).
• A Pencil and a Sticker
This activity poses the question "A pencil costs 59 cents, and a sticker costs 20 cents less. How much do a pencil and a sticker cost together?"
• Building Toward Fluency
The purpose of this task is to promote certain addition strategies that will help students learn to fluently add and subtract within 20.
• Buttons odd and even
The purpose of this task is for students to determine whether a set of objects (up to 20) has an odd or even number of elements. Students will also write an equation to express an even number as a sum of two equal addends and an odd number as a sum of two equal addends and 1.
• Counting Dots in Arrays
Students who work on this task will benefit in seeing that given a quantity, there is often more than one way to represent it, which is a precursor to understanding the concept of equivalent expressions.
• Delayed Gratification
The purpose of this task is for students to compare two options for a prize where the value of one is given \$2 at a time, giving them an opportunity to "work with equal groups of objects to gain foundations for multiplication."
• Grade 2 Math Module 1: Sums and Differences to 100 (EngageNY)
Module 1 sets the foundation for students to master sums and differences to 20. Students subsequently apply these skills to fluently add one-digit to two-digit numbers at least through 100 using place value understanding, properties of operations, and the relationship between addition and subtraction.
• Grade 2 Math Module 4: Addition and Subtraction Within 200 with Word Problems to 100 (EngageNY)
In Module 4, students develop place value strategies to fluently add and subtract within 100; they represent and solve one- and two-step word problems of varying types within 100; and they develop conceptual understanding of addition and subtraction of multi-digit numbers within 200. Using a concrete to pictorial to abstract approach, students use manipulatives and math drawings to develop an understanding of the composition and decomposition of units, and they relate these representations to the standard algorithm for addition and subtraction.
• Grade 2 Math Module 6: Foundations of Multiplication and Division (EngageNY)
Module 6 lays the conceptual foundation for multiplication and division in Grade 3 and for the idea that numbers other than 1, 10, and 100 can serve as units. Topics in this module include: Formation of Equal Groups, Arrays and Equal Groups, Rectangular Arrays as a Foundation for Multiplication and Division, and The Meaning of Even and Odd Numbers.
In order to assist educators with the implementation of the Common Core, the New York State Education Department provides curricular modules in Pre-K-Grade 12 English Language Arts and Mathematics that schools and districts can adopt or adapt for local purposes.
• Grade 2 Unit 2: Becoming Fluent with Addition and Subtraction (Georgia Standards)
In this unit students will cultivate an understanding of how addition and subtraction affect quantities and are related to each other, will reinforce the multiple meanings for addition (combine, join, and count on) and subtraction (take away, remove, count back, and compare), further develop their understanding of the relationships between addition and subtraction, recognize how the digits 0-9 are used in our place value system to create numbers and manipulate amounts and continue to develop their understanding solving problems with money.
• Grade 2 Unit 6: Developing Multiplication (Georgia Standards)
In this unit students will understand and model multiplication as repeated addition and as rectangular arrays, determine if a number is odd or even (within twenty) and create and interpret picture graphs and bar graphs.
• Hitting The Target Number
The purpose of this task is to help students develop flexible strategies for adding and subtracting within 20.
• IXL Game: Add and Subtract Numbers
This game helps second graders fluently add and subtract within 20 using mental strategies. This is just one of many online games that supports the Utah Math core. Note: The IXL site requires subscription for unlimited use.
• Operations and Algebraic Thinking (2.OA) - Second Grade Core Guide
The Utah State Board of Education (USBE) and educators around the state of Utah developed these guides for Second Grade Mathematics - Operations and Algebraic Thinking (2.OA)
• Partitioning a Rectangle into Unit Squares
The purpose of this task is to show the student that a rectangle can be partitioned into unit squares, and that there are a number of reasonable ways to count the resulting squares.
• Red and Blue Tiles
This task is specifically written so that students have opportunities to use different strategies to determine whether a set has an even or odd number of objects.
• Saving Money 2
The purpose of this task is for students to relate addition and subtraction problems to money and to situations and goals related to saving money. This problem shows the work advanced second graders might use for adding 2-digit numbers.

http://www.uen.org - in partnership with Utah State Board of Education (USBE) and Utah System of Higher Education (USHE).  Send questions or comments to USBE Specialists - Trish  French or Molly  Basham and see the Mathematics - Elementary website. For general questions about Utah's Core Standards contact the Director - Jennifer  Throndsen.

These materials have been produced by and for the teachers of the State of Utah. Copies of these materials may be freely reproduced for teacher and classroom use. When distributing these materials, credit should be given to Utah State Board of Education. These materials may not be published, in whole or part, or in any other format, without the written permission of the Utah State Board of Education, 250 East 500 South, PO Box 144200, Salt Lake City, Utah 84114-4200.