Grade 3 - Number
Standard 3.N.10 - Use properties of addition to find the missing number of an equation.
Included Skills: Number Properties, Addition
Apply mental mathematics strategies and number properties in order to understand and recall basic addition facts and related subtraction facts to 18. • Describe a mental mathematics strategy that could be used to determine a given basic fact, such as: - doubles; e.g., for 6 + 8, think 7 + 7. - doubles plus one; e.g., for 6 + 7, think 6 + 6 + 1. - doubles take away one; e.g., for 6 + 7, think 7 + 7 – 1. - doubles plus two; e.g., for 6 + 8, think 6 + 6 + 2. - doubles take away two; e.g., for 6 + 8, think 8 + 8 – 2. - making 10; e.g., for 6 + 8, think 6 + 4 + 4 or 8 + 2 + 4. - commutative property; e.g., for 3 + 9, think 9 + 3. - addition for subtraction; e.g., for 13 – 7, think 7 + ? = 13. • Apply the property of zero to determine a given sum or difference when adding or subtracting zero; e.g., 5 + 0 = 5 and 5 – 0 = 5. • Provide a rule for determining answers when adding and subtracting zero. • Apply a mental mathematics strategy to provide a solution to a given basic addition fact up to and including 9 + 9 or a related subtraction fact. • Demonstrate understanding, recall/memorization and application of addition facts up to and including 9 + 9 and related subtraction facts.