AK.1.NBT. Number and Operations in Base Ten
Use place value understanding and properties of operations to add and subtract.
1.NBT.4. Add using numbers up to 100 including adding a two-digit number and a one-digit number and adding a two-digit number and a multiple of 10.
1.NBT.4.a. Use concrete models or drawings and strategies based on place value; properties of operations; and/or relationship between addition and subtraction.
1.NBT.4.b. Relate the strategy to a written method and explain the reasoning used.
AK.1.OA. Operations and Algebraic Thinking
Add and subtract using numbers up to 20.
1.OA.5. Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
1.OA.6. Add and subtract using numbers up to 20, demonstrating fluency for addition and subtraction up to 10. Use strategies such as
1.OA.6.a. Counting on
1.OA.6.b. Making ten (8 + 6 = 8 + 2 + 4 = 10 + 4 = 14)
1.OA.6.e. Creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).
Understand and apply properties of operations and the relationship between addition and subtraction.
1.OA.3. Apply properties of operations as strategies to add and subtract. (Students need not know the name of the property.) For example: 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). Demonstrate that when adding zero to any number, the quantity does not change (Identity property of addition).
1.OA.4. Understand subtraction as an unknown-addend problem. For example, subtract 10 - 8 by finding the number that makes 10 when added to 8.