In this chapter students will practice 2-digit addition, with and without regrouping. Students will begin by breaking apart ones and finding a group of ten. They will circle ten ones and exchange it for a ten stick. When adding two numbers while using pictures, students will find which addend is closest to a ten, circle it, and regroup to the next place value. Students will also break apart addends into tens and ones and use expanded form to add up a number. After showing a number in base 10 form, students will use actual numerical digits to add and regroup. Students will also need to be able to determine whether a number needs regrouping or not. They will continue in using bar models (part-part-whole) in order to problem solve. It is also important that students are able to write their own addition equations to solve for a missing number. Finally, students will use prior knowledge in order to solve for problems with three or four addends.