Our district adopted Math Expressions as our math curriculum (below are pictures from my teachers' manual). This is our first year with Math Expressions and I am in LOVE with it! I previously blogged about the addition strategies the students have learned. With subtraction, the students learned three strategies: Common U.S. Method, Ungroup First Method, and Expanded Method. Again, the students use Proof Pictures to show the ungrouping in subtraction and how to "take away" from the bigger number.