Second graders reviewed the strategies to help them add and subtract multi-digit numbers this week. Partial sums method and regrouping were the focus for addition and the Trade-First method was the target strategy students utilized to solve given problems in class and for homework. Place value concepts were highlighted as students represented multi-digit numbers with Base-10 flats (100s), longs (10s) and cubes (1s). When manipulatives are not on hand, students reviewed how they can use Base-10 notation to represent their numbers while adding and subtracting.