Palmdale School District Mathematics Content Standards Grade 2 NUMBER SENSE Students: 2.1 understand and use the inverse relationship between addition and subtraction (e.g., an opposite number sentence for = 14 is = 8) to solve problems and check solutions.

Understanding the Fact Family relationship.

SUBTRACTIONADDITION Fact Family 6, 8, & = = = = 6

We are starting with A Total of Fourteen Apples

68 = 14 ADDITION

86= 14 ADDITION

SUBTRACTION 146 = 8

SUBTRACTION 148= 6

Understanding how to check your answers using Fact Families.

Defining Terms Sum Parts of an addition Problem = 14 Addend

We know that: = 14 How To Check ADDITION PROBLEMS With Subtraction Check answer by subtracting an addend from the sum: YOUR ANSWER SHOULD BE THE SECOND ADDEND!!!! = 8

We know that: = 14 How To Check ADDITION PROBLEMS With Subtraction Check answer by subtracting an addend from the sum: YOUR ANSWER SHOULD BE THE SECOND ADDEND!!!! = 6

Defining Terms Difference Parts of a subtraction Problem = 8 Starting Number Take Away Number

We know that: = 8 How To Check SUBTRACTION PROBLEMS With Addition Check answer by adding the answer to the take away number: YOUR ANSWER SHOULD BE THE STRATING NUMBER!!!! = 14

We know that: = 6 How To Check SUBTRACTION PROBLEMS With Addition Check answer by adding the answer to the take away number: YOUR ANSWER SHOULD BE THE STRATING NUMBER!!!! = 14

Practice Problems

EXAMPLE Directions:Make fact families out of the given numbers. Example: 2, 3, = = = = 2

GUIDED PRACTICE Part One Directions: Make fact families out of the given numbers. 1) 4, 5, 92) 2, 5, 7 3) 4, 7, 114) 8, 9, 17 Reminder: four problems make up a fact family: two addition and two subtraction.

GUIDED PRACTICE ANSWERS 1) 4, 5, = = = = 4 2) 2, 5, = = = = 2 3) 4, 7, = = = = 4 4) 8, 9, = = = = 8

EXAMPLE Directions: Solve the given problem, then check your answer using fact families. Example: = = 4 Problem: Check: Is the answer correct? Yes, because the check answer is the same as the other addend.

= = 10 EXAMPLE Directions: Solve the given problem, then check your answer using fact families. Example: Problem: Check: Is the answer correct? Yes, because the check answer is the same as the starting number.

GUIDED PRACTICE Part Two Directions: Solve the given problem, then check your answer using fact families. 1) =2) = 3) =4) =

GUIDED PRACTICE ANSWERS 1) = PROBLEM: = 13 2) = PROBLEM: = 7 3) = PROBLEM: = 13 4) = PROBLEM: = 7 CHECK: = 7 CHECK: = 12 CHECK: = 4 CHECK: = 16