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).

Standard 2.OA.3

Determine whether a group of objects (up to 20) has an odd or even number of members, (for example, by pairing objects or counting them by twos). Write an equation to express an even number as a sum of two equal addends.

• 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 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.
• 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.
• 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)
• 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.

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.