# Operations & Algebraic Thinking

Operations &Algebraic Thinking (OA)

Represent and solve problems involving addition and subtraction.

CCSS.MATH.CONTENT.1.OA.A.1

Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.1

CCSS.MATH.CONTENT.1.OA.A.2

Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

Understand and apply properties of operations and the relationship between addition and subtraction.

CCSS.MATH.CONTENT.1.OA.B.3

Apply properties of operations as strategies to add and subtract.2 Examples: If 8 + 3 = 11 is known, then 3 + 8 = 11 is also known. (Commutative property of addition.) To add 2 + 6 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4 = 2 + 10 = 12. (Associative property of addition.)

CCSS.MATH.CONTENT.1.OA.B.4

Understand subtraction as an unknown-addend problem. For example, subtract 10 - 8 by finding the number that makes 10 when added to 8.

CCSS.MATH.CONTENT.1.OA.C.5

Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).

CCSS.MATH.CONTENT.1.OA.C.6

Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 - 4 = 13 - 3 - 1 = 10 - 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 - 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).

Work with addition and subtraction equations.

CCSS.MATH.CONTENT.1.OA.D.7

Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6 = 6, 7 = 8 - 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2.

CCSS.MATH.CONTENT.1.OA.D.8

Determine the unknown whole number in an addition or subtraction equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = _ - 3, 6 + 6 = _.

Operations & Algebraic Thinking (OA) 1.OA.1

1.OA.A.1

Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

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Addition and Subtraction Word Problems 1

Operations & Algebraic Thinking (OA)

1.OA.A1

IXL Activities

Operations & Algebraic Thinking (OA) 1.OA.2

1.OA.A.2

Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

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Operations & Algebraic Thinking (OA)

1.OA.A2

IXL Activities

Operations & Algebraic Thinking (OA) 1.OA.3

1.OA.B.3

Apply properties of operations as strategies to add and subtract. Examples: If 8 + 3 = 11 is known, then 3 + 8 = 11 is also known. (Commutative property of addition.) To add 2 + 6 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4 = 2 + 10 = 12. (Associative property of addition.)

Watch This Video

Videos for this standard are coming soon to Khan Academy.  Fact Triangle Fact Family

3 + 4 = 7

4 + 3 = 7

7 – 4 = 3

7 – 3 = 4

## Khan Academy: Apply properties of operations as strategies to add and subtract.

Do these activities: KHAN ACADEMY 1.OA.B.3 ACTIVITIES (Coming Soon)

Operations & Algebraic Thinking (OA) 1.OA.4

1.OA.B.4

Understand subtraction as an unknown-addend problem. For example, subtract 10 – 8 by finding the number that makes 10 when added to 8.

Watch This Video

Operations & Algebraic Thinking (OA)

1.OA.B4

IXL Activities

Operations & Algebraic Thinking (OA) 1.OA.5

1.OA.C.5

Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).

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Skills for this standard are coming soon to Khan Academy.

Do these activities: KHAN ACADEMY 1.OA.C.5 ACTIVITIES (Coming Soon)

Operations & Algebraic Thinking (OA)

1.OA.C5

IXL Activities

Operations & Algebraic Thinking (OA) 1.OA.6

1.OA.6

Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 – 4 = 13 – 3 – 1 = 10 – 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 – 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).

Watch This Video

Operations & Algebraic Thinking (OA)

1.OA.C6

IXL Activities

Operations & Algebraic Thinking (OA) 1.OA.7

1.OA.D.7

Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6 = 6, 7 = 8 – 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2.

Watch This Video

Operations & Algebraic Thinking (OA)

1.OA.D7

IXL Activities

Operations & Algebraic Thinking (OA) 1.OA.8

1.OA.D.8

Determine the unknown whole number in an addition or subtraction equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = ? – 3, 6 + 6 = ?.

Watch This Video

Operations & Algebraic Thinking (OA)

1.OA.D8

IXL Activities

Operations and Algebraic Thinking (OA) Games

Represent and solve problems involving addition and subtraction.

Understand and apply properties of operations and the relationship between addition and subtraction.

Work with addition and subtraction equations.

Number Bonds 10 (Easy)

Combine number balls to make sums of 10.

Number Bonds 20 (Medium)

Combine number balls to make sums of 20.

Number Bonds 30 (Medium-Challenging) Combine number balls to make sums of 30.

Number Bonds 40 (Challenging)

Combine number balls to make sums of 40.

Practice sums and addition facts in this exciting math game.

Practice sums within 20 and addition facts.

Practice sums within 20 and addition facts with this fun-filled math game.

Choose one or more addends. Can you make all 12 monster friends appear?

Move the friendly zogs to the correct sums without being captured.

Choose a target sum (10 to 20) to practice. Place the puzzle piece on the number in the grid.

Practice sums of 10and addition facts by clicking two fur balls that make 10.

Add two-digit numbers correctly to win the race.

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Subtraction Games

Island Chase

Practice subtraction facts (within 20) with a fun math game in a tropical setting.

Sailboat Tug

Practice subtraction facts (within 20) with a fun math game in a tropical setting.

Math Monster Subtraction

Choose one or more numbers to subtract. Can you make all 12 monster friends appear?

Ducky Race Subtraction (Challenging)

Practice subtraction facts in a duck racing math game. (Positive and Negative Numbers)

Minus Mission (Challenging)

Practice subtraction facts with a space-themed math game.

Puzzle Pics Subtraction Choose the largest starting number (10 to 20). Place the puzzle piece on the missing number in the grid.