2.MD.A.4: Measuring Length Differences: Relating Addition and Subtraction to Measurement
2.NBT.B.5: Fluent Addition and Subtraction within 100: Strategies Using Place Value and Operational Properties
2.NBT.A.1: Three-Digit Numbers: Hundreds, Tens, and Ones
2.OA.A.1: Solving Word Problems with Addition and Subtraction within 100: One- and Two-Step Strategies
