Unit 6 Topic 2: Combinations of Numbers
Common Core Standards: Operations and Algebraic Thinking
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 unknownaddend problem. For example, subtract 10  8 by finding the number that makes 10 when added to 8. Add and subtract within 20. 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). 



2.1 Revisiting How Many of Each Problems?
Revisiting How Many of Each? Problems
 Finding relationships among different combinations of a number
 Finding as many 2addend combinations of a number as possible
 Trying to prove that all the possible 2addend combinations of a number have been found
2.2 Crayon Puzzles About More
Crayon Puzzles about More


2.3 Dot Addition
Dot Addition: Students play a new variation of this game.
Classroom Routine: Quick Survey: Have a brother? Have a sister?
 Adding 2 or more singledigit numbers
 Using numbers and standard notation (+, −, =) to record
Classroom Routine: Quick Survey: Have a brother? Have a sister?
2.4 More Crayon Puzzles
Crayon Puzzles
Classroom Routine: Start with/Get to 

Math and Literature Lesson
Bean Thirteen
Task: What are all the fair and unfair ways you can share 12 beans with 3 people?
Bean Thirteen
Task: What are all the fair and unfair ways you can share 12 beans with 3 people?
2.5 Assessment: Ten Crayons in All & How Many Days Routine
 Finding as many 2addend combinations of 10 as possible
 Reasoning about more, less, and equal amounts
 Adding 2 or more singledigit numbers
2.6A True or False?

