2.NBT.9.+Explain+why+addition+...

Number and Operations in Base Ten 2.NBT 9. Explain why addition and subtraction strategies work, using place value and the properties of operations.
 * Use place value understanding and properties of operations to add and subtract. **

Pgs. 65 – 76; 94 – 111; 157 – 185
 * __ Combining and Comparing __ : Close to 100 (Investigation 1: 1 - 2)
 * __ Putting Together and Taking Apart __ : Working Within 100 (Investigation 2: 1 - 4)
 * __ Putting Together and Taking Apart __ : Capture 5 (Investigation 5: 2 - 3)
 * John Van de Walle and LouAnn Lovin, __Teaching Student-Centered Mathematics K-3__:
 * Origo:A//ddition/Subtraction// // Fluency Kits; Mathementals 2; //// Think Tanks //

__ Bridges in Mathematics __

//**Think Math**// Lessons 2.9; 10.6 - 10.12