### The resources above correspond to the standards listed below:

#### Maryland College and Career-Ready Standards

MD.MA.2.OA. Operations and Algebraic Thinking (OA)
2.OA.A. Represent and solve problems involving addition and subtraction.
2.OA.A.1. Major Standard: Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings, and equations with a symbol for the unknown number to represent the problem.
2.OA.A.1.1. Ability to explore addition and subtraction with manipulatives to build their conceptual understanding (e.g., snap cubes, subitizing cards, tens frames, hundreds charts, number lines and empty number lines).
2.OA.A.1.2. Ability to take apart and combine numbers in a wide variety of ways.
2.OA.A.1.7. Ability to apply the knowledge of addition and subtraction to choose the most efficient strategy to solve a problem.
2.OA.B. Add and subtract within 20.
2.OA.B.2. Major Standard: Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.
2.OA.B.2.1. Ability to apply counting strategies to develop automatic recall.
2.OA.B.2.2. Ability to use reasoning strategies to make use of known facts (e.g., sums of ten, making ten, doubles, near doubles/inside doubles, doubles plus, counting on).
MD.MA.2.NBT. Number and Operations in Base Ten (NBT)
2.NBT.A. Understand place value.
2.NBT.A.1a. Major Standard: Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones – Understand the following as a special case: 100 can be thought of as a bundle of ten tens–called a “hundred”.
2.NBT.A.1a.1. Ability to compose and decompose 100 in a variety of ways lays foundation for regrouping.
2.NBT.B. Use place value understanding and properties of operations to add and subtract.
2.NBT.B.6. Major Standard: Add up to four two-digit numbers using strategies based on place value, properties of operations.
2.NBT.B.6.1. Knowledge of and ability to apply strategies such as expanded form, empty number line and partial sums.
2.NBT.B.7. Major Standard: Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
2.NBT.B.7.1. Represent addition and subtraction three digit numbers within 1000 using concrete models or drawings and place value strategies, properties of operations, and/or the relationship between addition and subtraction. Then relate the strategy to a written method.
2.NBT.B.9. Major Standard: Explain why addition and subtraction strategies work, using place value and the properties of operations.
2.NBT.B.9.2. Ability to reason mathematically and explain why their chosen strategy works using words, pictures, and/or symbols to support their explanation.