NC.2.OA.4

Arrays

Domain

Operations and Algebraic Thinking

Number and Operations in Base Ten

Cluster

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

Understand place value.

Standard(s)

NC.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.

NC.2.NBT.2 Count within 1000; skip-count by 5s, 10s, and 100s.

Materials

BLM- Picture of 5 by 5 array of stars, pencil, objects or counters available.

Task

Provide materials to the student.  Read the problem to the student: How many stars are in the box?  Write an equation with equal addends to express the total.

Continuum of Understanding

Not Yet Proficient

·      Needs prerequisite skills

Progressing

·      Counts by ones to determine total amount.

·      If skip counts, counts by groups other than 5.

·      If skip counts, counts by 5 incorrectly.

·      Equation does not illustrate five groups of 5. 

Strategy(ies) Used:

q  Skip Counts

q  Makes Tens

q  Basic Facts

q  Creates easier or known sums

q  Doubles

q  Other:

Meets Expectation

·      Equation indicates the there are five groups of 5.

     (5 + 5 + 5 + 5 + 5 = 25).

·      Correctly determines that there are 25 stars in the box.

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.