Chapter 3

Upon completion of Unit 3:

• 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.OA.B.3. Apply properties of operations as strategies to add and subtract.
• 1.OA.C.5. Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
• 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).
• 1.OA.D.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.
• 1.OA.D.8. Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers.
• MP.2. Reason abstractly and quantitatively.
• MP.4. Model with mathematics.
• MP.5. Use appropriate tools strategically.
• MP.6. Attend to precision.
• MP.8. Look for and express regularity in repeated reasoning