NC.2.OA.4

Array of Tiles

Domain

Operations and Algebraic Thinking

Cluster

Work with equal groups of objects to gain foundations for multiplication.

Understand place value.

Standard(s)

2.OA.4 Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.

Materials

Pencil, paper, 16 square tiles.

Task

Provide the materials to the student.  Read the problem to the student: Use 8 tiles to make an array.  Describe the array.  Prompt if needed: How many rows are there?  How many columns are there?  Then say: Draw a picture of your array. Write an equation to illustrate your array.

When the student has finished with the first array, say: Use 8 more tiles to make a different array.  Describe the array.  Prompt if needed: How many rows are there?  How many columns are there?  Then say: Draw a picture of your array. Write an equation to illustrate your array.

Continuum of Understanding

Not Yet Proficient

·      Needs prerequisite skills

Progressing

·      Uses 8 tiles, but does not create an array.

·      Creates one array but does not create a second array that is different or correct.

·      If skip counts, counts incorrectly.

·      Drawing(s) does not represent array(s) created.

·      Equation(s) does not indicate repeated groups.

Strategy(ies) Used:

q  Skip Counts

q  Makes Tens

q  Basic Facts

q  Creates easier or known sums

q  Doubles

q  Other:

Possible Solutions:

1 row of 8 

8 + 0

8 rows of 1

1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 = 8

4 rows of 2

2 + 2 + 2 + 2 = 8

2 rows of 4

4 + 4 = 8

Meets Expectation

·      Creates two different arrays with the tiles.

·      Drawings accurately represent arrays created.

·      Equations indicate repeated groups

(e.g., 2 + 2 + 2 + 2 = 8).

Standards for Mathematical Practice

1.  Makes sense and perseveres in solving problems.

2.  Reasons abstractly and quantitatively.

3.  Constructs viable arguments and critiques the reasoning of others.

4.  Models with mathematics.

5.  Uses appropriate tools strategically.

6.  Attends to precision.

7.  Looks for and makes use of structure.

8.  Looks for and expresses regularity in repeated reasoning.