2.OA.C.4
Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.
Use addition to find the total number of objects arranged in rectangular arrays, with up to 5 rows and 5 columns. See that we could add in two different ways. That is, we could add along the rows or along the columns. Here's an excellent demonstration. Here's where students can practice. Next, students will solve word problems, some involving arrays, and others involving just repeated addition. Two excellent lessons can be found here and here. The aforementioned skills will prepare students for multiplication and the idea that multiplication is commutative. However, multiplication shouldn't be mentioned at this time. Conclude by exploring this game.