Domain

Operations and Algebraic Thinking

Cluster

Work with equal groups.

Standard(s)

NC.2.OA.3  Determine whether a group of objects, within 20, has an odd or even number of members by:

●       Pairing objects, then counting them by 2s

●       Determining whether objects can be placed into equal groups

●       Writing an equation to express an even number as the sum of two equal addends

Materials

student form, pencil, cubes or other manipulatives (optional)

Task

State to students:  These numerals represent the number of people in a group.  Decide if each group of people has an odd number of members or an even number of members. Circle odd or even. Justify your answers. Write an equation with two addends that represents that group.  If the number is even, write an equation that proves the number is even.   

Continuum of Understanding

Not Yet Proficient

Needs prerequisite concepts:

Checklist for teacher to identify mastery of standard:

❑    Pairs group members or puts them into two equal groups

❑    Clear justification

❑    Writes an equation with two addends that represents that group (addends can be equal if there are an even number of group members)

Progressing

Student does one or two of the following:

●   Correctly identifies group as odd or even

●   Explanation justifies even/odd concept

●   Equation represents grouping (addends are equal if there are an even number of group members)

Meets Expectation

●   Correctly pairs groups as even or odd by pairing members or divides group into two parts

●   Clear justification

●   Writes an equation to correctly express group members with two addends.

●   Recognizes that only even numbers can have equations with equal addends. (6 + 6 = 12)