Term 1 Big Ideas:
Gr. 2 – Numbers to 100 represent quantities that can be decomposed into 10s and 1s
Gr. 3 – Development of computational fluency in addition and subtraction of whole numbers requires flexible decomposing and composing

Currently, math lessons are geared towards building strong number sense and developing flexibility in calculating with numbers.

References:
Adding & Subtracting Double Digits with Regrouping
   

Video:  Subtraction with Regrouping

 Vocabulary:  digit, add, subtract, sum, difference, compose & decompose, addend & minuend