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K-5 Grade 2 Unit 8 Lesson 7

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•K-5 Math 6-8 Math 9-12 Math

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Kindergarten Grade 1 •Grade 2 Grade 3 Grade 4 Grade 5

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Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 Unit 7 •Unit 8 Unit 9

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Lesson 1 Lesson 2 Lesson 3 Lesson 4 Lesson 5 Lesson 6 •Lesson 7 Lesson 8 Lesson 9 Lesson 10 Lesson 11 Lesson 12 Lesson 13 Lesson 14

K-5
6-8
9-12

Kindergarten
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Grade 4
Grade 5

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Unit 3
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Unit 9

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Lesson 7

Warm-up Activity 1 Activity 2

Unit 8, Lesson 7

What Is an Array?

Grade 2

Warm-up

Which 3 go together?

Group of circles. 3 rows of 3 circles. Column 1, 4. Column 2, 2. Column 3, 3. Column 4, 2. Column 5, 1. — A

Array. 3 rows of 4. — B

Group of circles. 3 columns of 3 circles. Row 1, 1. Row 2, 2. Row 3, 3. Row 4, 2. Row 5, 1. — C

3 rows of 3 circles. Large space between Column 1 and Column 2. Circles in Column 2 overlap with circles in Column 3. — D

Activity 1

Arrange each set of counters into equal-size rows with no leftovers.

How many counters are there in all? _____
Show or explain how you arranged them using drawings, numbers, or words.
How many counters are there in all? _____
Show or explain how you arranged them using drawings, numbers, or words.
How many counters are there in all? _____
Show or explain how you arranged them using drawings, numbers, or words.

Activity 2

1. How many rows are in this array?
2. How many counters are in each row?
3. How many counters are there in all?
1. How many rows are in this array?
2. How many counters are in each row?
3. How many counters are there in all?
Use 6 counters. Make 2 rows with the same number in each row. How many counters are in each row?
Use 20 counters. Make 4 rows with the same number in each row. How many counters are in each row?

Standards Alignment

Building On

2.OA.2

Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.

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2.OA.3

Determine whether a group of objects (up to 20) has an odd or even number of members, e.g., by pairing objects or counting them by 2s; write an equation to express an even number as a sum of two equal addends.

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Addressing

Building Toward

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.

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Standards Alignment

Building On

Addressing

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.

View Full Standard

Building Toward

Standards Alignment

Building On

Addressing

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.

View Full Standard

Building Toward