First Grade Operations and Algebraic Thinking 

Introduction to addition and subtraction equations, properties of operations and word problems. Just click on the blue links to display or print pdfs. 

Standards 
Practice
Pages


Represent and solve problems involving addition and subtraction  Cluster 1 

Standard 1.OA.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.  Add Objects Answers 1.OA.1.a 
Subtract Words Answers 1.OA.1.b 
Standard 1.OA.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.  Count Objects Answers 1.OA.2.a 
Mixed Equations Answers 1.OA.2.b 
Understand and apply properties of operations and the relationship between addition and subtraction  Cluster 2 

Standard 1.OA.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 + 5 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4  2 + 10  12. (Associative property of addition.)  Commutative Counting Answers 1.OA.3.a 
Associative Property Answers 1.OA.3.b 
Standard 1.OA.4: Understand subtraction as an unknownaddend problem. For example, subtract 10  8 by ﬁnding the number that makes 10 when added to 8.  Take Away Objects Answers 1.OA.4.a 
Subtraction and Addition Answers 1.OA.4.b 
Add and subtract within 20  Cluster 3 

Standard 1.OA.5: Relate counting to addition and subtraction (e.g., by counting on 2 to add 2)  AddSubt by 1s Answers 1.OA.5.a 
AddSubtract Answers 1.OA.5.b 
Standard 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).  Add Fluently Answers 1.OA.6.a 
Subtraction to Addition Strategy Answers 1.OA.6.b 
Work with addition and subtraction equations  Cluster 4 

Standard 1.OA.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.  Compare Number of Shapes Answers 1.OA.7.a 
Compare Equations Answers 1.OA.7.b 
Standard 1.OA.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 = ?.  Add Shapes Answers 1.OA.8.a 
Missing Numbers Subtract Answers 1.OA.8.b 